MECHANICAL IMPORTANT CONCEPT QUESTIONS
1. The axes of a three-cylinder air compressor are at 120° to one another and their connecting rods are coupled to a single crank. The length of each connecting rod is 240 mm and the stroke is 160 mm. The reciprocating parts have a mass of 2.4 kg per cylinder. What is the maximum value of primary force if the engine runs at 1800 rpm? 2. A porter governor has a maximum and minimum speed of 200 rpm and 150 rpm respectively. If the effective load on the sleeve is 30 kgf. The governor efforts would be ___________ kgf 3. A uniform disc of 50 kg mass, 800 mm diameter and 840 rpm rotational speed is mounted on a shaft. The plane of the disc is not perfectly at right angles to the axis of the shaft but has an error of 1.5 degree. The gyroscopic couple acting on the bearing is _________ Nm. 4. Each ball of a Porter governor has a mass of 6 kg and the mass of the sleeve is 40 kg. The upper arms are 300 mm long and are pivoted in the axis of rotation where as the lower arms are 250 mm long and are attached to the sleeve at a distance of 40 mm from axis and radius of the governor is 150 mm. What will be the power of governor for 1% change in speed. 5. A four-cylinder in-line reciprocating engine is shown in the diagram given below. The cylinders are numbered 1 to 4 and the firing order is 1-4-2-3 : Both primary and secondary forces are balanced 6. A wheel rotates with a constant acceleration of 2.0 rad/s 2. If the wheel starts from rest, the number of revolutions it will make in the first 10 sec will be _______. 7. An aeroplane makes a complete half circle of 50 meters radius, towards left, when flying at 200 km per hr. The rotary engine and the propeller of the plane has a mass of 400 kg and a radius of gyration of 0.3 m. The engine rotates at 2400 rpm clockwise when viewed from the rear. Find the gyroscopic couple on the aircraft ____________ kN-m. 8. In a damped spring-mass system, if the mass is halved and the spring stiffness is doubled, the logarithmic decrement is…….. 9. What will be the frequency of torsional vibrations of the disc shown in figure. If both the ends of the shafts are fixed and the diameter of the shaft is 40 mm. The disc has a mass of 96 kg and radius of gyration of 0.4 m. Take modulus of rigidity for the shaft material is 85 GPa. L1 = 1 m and L2 = 0.8 m. 10. For the system shown in figure, the cantilever beam has flexural rigidity EI, the time period of oscillation is 11. A block of mass 10 kg executes simple harmonic motion under the restoring force of a spring. The amplitude and time period of the motion are 0.2 m and 3.14 s respectively. The maximum force exerted by the spring on the block in N is ___________. 12. A 13.6 kg block is supported by the spring arrangement as shown. If the block is moved from its equillibrium position 44 mm vertically downward and released, the maximum acceleration of the block is ___________ m/s2. 13. What will be the natural frequency of the system shown below in _________ Hz.
MD 14. If the heat generated in the bearing is 300 J, load acting on the bearing is 16,000 N and bearing has a speed of 600 rpm, the diameter of journal bearing is _________ mm. [Take coefficient of friction as 0.01]. 15. A shaft can safely transmit 180 kW while rotating at a given speed. If this shaft is replaced by a shaft of diameter double of the previous one and rotated at half the speed of the previous, the power that can be transmitted by the new shaft is __________ Kw 16. Two plates are joined together by means of single transverse and double parallel fillet welds as shown in the given figure. If the size of fillet is 5 mm and allowable shear load per mm is 300 N, what is the approximate length of each parallel fillet? 17. A helical spring is made from a wire of 6 mm diameter and has outside diameter of 75 mm. If the permissible shear stress is 350 MPa and modulus of rigidity 84 kN/mm 2. By considering the effect of curvature the deflection per active turn will be 18. A multiplate disc clutch transmits 55 kW of power at 1800 rpm. The coefficient of friction for the friction surfaces is 0 .1. Axial intensity of pressure is not to exceed 160 kN/m 2. The ratio of internal radius to external radius of clutch is 0.7 and internal radius is 80 mm. Then the number of plates needed to transmit the required torque is _____________. 19. Water is flowing through a 200 mm diameter pipe with coefficient of friction f = 0.04. The shear stress at a point 40 mm from the pipe axis is 0.00981 N/cm 2. The shear stress at the pipe wall will be _____________ N/cm2. 20. A multi-disc clutch employs 3 steel and 2 bronze discs having outer diameter of 300 mm and inner diameter of 175 mm. If the coefficient of friction is 0.25 and axial force on each pair of surfaces is 5 kN, then the torque transmitted assuming uniform wear is _________ N-m. 21. A shaft rotating at constant speed has variable load applied to it. The radial load on a bearing is F1 equal to 3 kN for 1 second, F2 equal to 1.5 kN for 2 seconds, and F3 equal to 500 N for 3 seconds. If the load variation subsequently repreats itself then the equivalent load Fm is __________ kN. FM 22. An orifice meter with Cd = 0.61 is substituted by venturimeter with Cd = 0.98 in a pipeline carrying crude oil, having the same throat diameter as that of the orifice. For the same flow rate, the ratio of the pressure drops for the venturimeter and the orifice meter is __________. 23. A vertical venturimeter 40 cm × 20 cm is provided in a vertical pipe to measure the flow of oil of relative density 0.80. The difference in elevations of the throat section and entrance section is 0.5 m, the direction of flow of oil being vertically upwards. The oil mercury
differential gauge shown deflection of mercury (SHg = 13.6) equal to 40 cm as shown in figure. The quantity of oil flowing in the pipe (Neglect losses). 24. A particle moves along a curve whose parametric equations are x = t3 + 2t, y = – 3e–2t and z = 2 sin(5t ), where x, y and z show variations of distance covered by the particle (in cm) with time t (in s). The magnitude of the acceleration of particle (in cm/s 2) at t = 0 is ____________ . 25. The flow of water (mass density = 1000 kg/m 3 and kinematic viscosity = 10–6 m2/s) in a commercial pipe, having equivalent roughness ks as 0.12 mm yields an average shear stress at the pipe boundary = 600 N/m2. The value of ks /δ′ (δ′ being the thickness of laminar sub layer) for this pipe is 26. A pipe of 0.7 m diameter has a length of 6 km and connects two reservoirs A and B. The water level in reservoirs A is at an elevation 30 m above the water level in reservoir B. Halfway along the pipeline, there is a branch through which water can be supplied to a third reservoir C. The friction factor of the pipe is 0.024. The quantity of water discharge into reservoir C is 0.15 m3/s. Considering the acceleration due to gravity as 9.81 m/s2 and neglecting minor losses the discharge (in m3/s) into the reservoirs B is __________. HMT 27. In order to increase rate of heat transfer metal rods are used as fins. If the long metal rods have dia 15 cm and coefficient of heat transfer as 15 W/m 2K. The minimum value of ‘k’ so that the use of fin is justified is _____________W/mK. 28. A cylindrical uranium fuel rod of radius 5 mm in a nuclear power plant is generating heat at the rate of 4 × 107 W/m3. The rod is cooled by a liquid (convective heat transfer coefficient 1000 W/m2K) at 25°C. At steady state, the surface temperature (in K ) of the rod is…. 29. In a flow over flat plate, water with velocity 6 m/s and stanton number = 0.3096 × 10 –3, if velocity is doubled with stanton number remaining constant. Then the new heat transfer coefficient will be _________ W/m2K. Use ρ = 1000 kg/m3 k = 4.2 W/Mk cp = 4.18 kJ/kgK 30. Solar radiation of 1200 W/m2 falls perpendicularly on a gray opaque surface of emissivity 0.5. If the surface temperature is 50°C and surface emissive power is 600 W/m 2, the radiosity of that surface will be _____________W/m2 THERMODYNAMICS 31. The piston of a vertical piston-cylinder device containing a gas has a mass of 40 kg and cross-sectional area 0.04 m2. The atmospheric pressure is 0.95 bar. The pressure inside the cylinder is
32. In a piston-cylinder arrangement, the pressure is inversely proportional to the square of volume. The initial pressure is 10 bar in cylinder and initial volume is 0.1 m 3. The volume is now changed so that the final pressure is 2 bar. The work done is 33. If a certain amount of steam is produced at a pressure of 8 bar and dryness fraction 0.8. What is the internal latent heat of steam at 8 bar ?Vg=0.240 Hfg=2046.5 34. A 100 kg block of iron casting at 500 K is thrown into a large lake that is at a temperature of 285 K. The iron block eventually reaches thermal equilibrium with the lake water. Assuming on average specific heat of 0.45 kJ/kgK for the iron, the entropy generated during the process is ______ kJ/K. 35. The ratio of work input needed to isentropically compress the saturated steam from 1 bar to 5 bar and work input needed to isentropically compress the saturated water for the same pressure ratio is ______________.H1=2675 at 1 bar H2 for superheated steam at 5 bar specific volume of water=0.001043 36. A 100 ohm resistor carrying a constant current of 1A is kept at a constant temperature of 27°C by a stream of cooling water for a time-interval of 1s, the change in entropy of resistor is________ J/K 37. A fan is to accelerate quiescent air to a velocity of 8 m/s at a rate of 9 m 3/s. The density of air is 1.18 kg/m3. The minimum power to be supplied to fan is ________ W 38. A gas undergoes a reversible adiabatic compression process in compressor from 0.5 MPa, 0.2 m3 to 0.05 m3. It follows the law PV 1.3 = constant. What is the change in enthalpy during the process? 39. Consider the expansion of air through a very small constriction in a pipe from pressure and temperature, respectively of 8 bar and 600 K to pressure of 1.2 bar. Assume air to be an ideal gas. The temperature of surroundings is 25°C. Then the Irreversibility associated with the expansion will be ____________ kJ. RAC 40. A building requires a 2-tonne heat pump for maintaining the interior space at 27°C when the outside temperature is 5°C. The heat pump operates on the normal vapour compression cycle and uses R- 134a as the working fluid. The heat pump operating conditions require an evaporator pressure of 240 kPa and a condenser pressure of 1600 kPa while the compressor has an isentropic efficiency of 85 percent.
The COP of heat pump is
41. A 6 m × 6 m × 4 m room contains air at 25°C and 100 kPa at a relative humidity of 75 percent. The enthalpy per unit mass of the dry air is _______ kJ/kg d.a. [Take Psat at 25°C = 3.1698 kPa]. 42. In a 3 ton capacity water cooler, water enters at 30°C and leaves at 15°C steadily. The water flow rate is __________ kg/hr. 43. An air-conditioned room of volume 20 m 3 has infiltration of air equivalent to 4 air changes per hour. Density of air is 1.2 kg/m3, specific heat cp is 1 kJ/kgK and temperature difference between room and ambient air is 40 K. The sensible heat load due to infiltrated air is _____________kW. 44. A stream of moist air (mass flow rate = 10.2 kg/s) with humidity ratio of 0.02 kg/kg dry air mixes with a second stream of superheated water vapour flowing at 0.4 kg/s. Assuming proper and uniform mixing with no condensation, the humidity ratio of the final stream (in kg/kg dry air) is
TURBO MACHINE 45. A centrifugal pump handles liquid whose kinematic viscosity is three times that of water. The dimensionless specific speed of the pump is 0.183 revolution and it has to discharge 2 m 3/s of liquid against a total head of 15 m then the speed (rev/s) of the turbine is ________. 46. A gas turbine plant operates on Brayton cycle using an optimum pressure ratio for maximum net work output and a regenerator of 100% effectiveness. If the maximum and minimum temperatures of the cycle are 800°C and 30°C respectively, the maximum network output per kg is _________ Kj PRODUCTION 47. While cooling, a cubical casting of side 50 mm undergoes 4%, 5% and 6% volume shrinkage during the liquid state, phase transition and solid state respectively. The volume of metal compensated from the riser is _________%
48. An aluminium billet of 250 mm diameter is extruded with an extrusion ratio 10. If the effective flow stress in compression is 300 MPa. Then the ideal extrusion pressure (in MPa) is _________ 49. It is required to reduce the 15 mm diameter of steel to 12 mm with a die. The semidie angle is 8° and the coefficient of friction is 0.06. Mean flow stress is given as 700 MPa. Then the drawing stress would the _____MPa. 50. In a single-pass rolling process, a 100 × 10 mm, sheet is rolled to 8 mm thickness. The roll radius is 220 mm and rotational speed is 100 rpm. The mean flow stress in tension is 180 N/mm2. Further, this reduction is the maximum possible in a single pass. The sheet thickness at neutral plane is 9 mm. The forward slip is 51. A 4 mm thick steel plate is cut in a shearing machine and the length of cut is 400 mm. The shear strength of the material is 200 MPa. If the cutting blade is inclined at 2 degree and percentage penetration is 45%, then the force required will be __________ kN. 52. The part shown in figure is to be blanked from a steel strip of 3 mm thickness. Assuming ultimateshear strength of the material to be 200 MPa. The force required for blanking operation would be ___________ kN.
53. A steel of diameter 10 mm is reduced to 7 mm diameter with a semi-die angle of 5° and coefficient of friction = 0.09, flow curve equation of material is σf = 1300ε0.3 MPa. Then the drawing stress is ___________ MPa. 54. A 0.9 m thick plate is welded by manual arc welding process using welding current of 150 A, arc voltage of 20 V and welding speed of 5 mm/s. If the process officiency is 0.8 surface resistance is 36 micro-ohm, the heat input will be 55. Spot welding of two 2 mm thick sheets of steel (density = 7000 kg/m 3) is carried out successfully by passing a certain amount of current for 0.1 second through the electrodes. The resultant weld nugget formed is 6 mm in diameter and 1.6 mm thick. If latent steel of fusion of steel is 1500 kJ/kg and effective resistance is 200 μΩ. Then the current passing through the electrodes is 56. In a arc welding process of steel with a potential of 25V and current of 200A, the travel speed is 5 mm/sec and the cross-sectional area of joint is 20 mm 2. Heat required to melt steel
may be taken as 10 J/mm 3 and the heat transfer efficiency as 0.80. Then melting effciency is _________ %. 57. The voltage arc length characteristic of a power source is V = 10 + 20 L, where V = operating voltage in volts and L = arc length in cm. The open circuit voltage for arc lengths ranging from 2 to 4 mm and current from 300 to 400 amps during welding operation is __________ volts. 58. A circular disc of 400 mm diameter and 100 mm height is to forged to 50 mm height. If the materials follows the flow equation, σf = 200 (0.02 + ε)0.42 MPa, then flow stress is equal to __________ MPa. 59. Cylindrical pins of diameter
are electroplated in a shop. Thickness the plating is
micron. Neglecting gage tolerance, the sized of the Go gage in mm to inspect the plated component is 60. Observation of a slip gauge on flatness interferometer produced fringe counts numbering 10 and 14 for two readings. The second reading is taken by rotating the setup by 180°. Assume that both faces of the slip gauge are flat and the wavelength of the radiation is 0.5086 mm. The parallelism error (in mm) between the two faces of the slip gauge is ___________ μm. 61. A standard machine tool and an automatic machine tool are being compared for the production of component. Following data refers to the two machine
What is the breakeven production batch size above which the automatic machine tool will be economical to use? 62. A bush manufacturing company has a contract to supply 5000 bushes to an automobile factory per day. The company has capacity to manufacture 8000 bushes and holding cost of 1000 bushes is 8 paise. Set up cost is Rs. 20. The length of production cycle is approximately 63. If orders are placed once a month to meet an annual demand of 6000 units, then the average inventory would be __________ units. 64. The following information is provided for an Annual usage = 12,000 units, ordering cost=Rs60 per Carrying cost = 10% of unit cost, unit cost of item = Rs. 10 and lead time = 10 There are 300 working days/year. In the past two years the use rate has gone as high
item: order days. as 70
units per day. For a reordering system based on the inventory level, the average inventory (units) is 65. The demand for a commodity is 100 units per day. Every time an order is placed, a fixed cost of Rs. 800 is incurred. Holding cost is Rs. 0.16 per unit per day. If the lead time is 12 days, the reorder point is 66. For maximization Linear Programming Problem, the objective function coefficient for an artificial variable is 67. The arrival rate of customers at a banking counter follows Poisson distribution with a mean of 45 per hour. The service rate of the counter clerk is 60 per hour. The probability in percentage, of 5 customers in the queue is ___________. 68. Maximize Z = 2x1 subject 2x1 + x2 x1 – x 2 x1, x2 The solution to the LPP is
+ 3x2 to ≤ 6 ≥ 3 ≥ 0 above
69. Complementary function (CF ) for differential equation
70. The degree of differential equation
71. Let the eigen values of matrix [A]2 × 2 are α and β then eigen values for (A + 5I)–1 are 72. The natural frequency of vibration of the following system is ______________ rad/s. [Take g = 10 m/s2, EI = 200 Nm for the beam]
73. An exhaust fan, rotating at 1000 rpm is to be supported by four springs, each having stiffness kN/m. If only 10% of the unbalanced force is to be transmitted to the base, the value of K is _____ N/m. Assume mass of the fan is 40 kg. 74. The entropy of fixed amount of an ideal gas
decreases in every isothermal compression
increase in every isothermal compression
remains same in every isothermal compression
may increase or decrease in every isothermal compression 75. A tank fully insulated contains 1 m 3 of air at 50°C and 2 MPa. The valve is open and air escapes until half the original mass is gone and then the valve is closed. After valve is closed, the pressure inside the tank is 76. 100 kJ of energy is transferred from a heat reservoir at 1000 K to a heat reservoir at 500 K. The ambient temperature is 300 K. The loss of available energy due to heat transfer processes is __________ kJ. 77. Air enters an air turbine at a pressure of 700 kPa, 65°C with a velocity of 90 m/s and leaves the turbine at 140 kPa, 5°C and 60 m/s velocity. There is no heat transfer from the turbine. Assume air to be an ideal gas with constant specific heat. The second law efficiency of the turbine is _________%. (Assume T0 = 25°C, p0 = 101.325 kPa 78. The specific enthalpy of the working fluid is labelled on the diagram in kJ/kg. The steam flow rate is 12600 kg/hr. The thermal efficiency of the plant is ____________%.
79. The time study data of a lathe in a factory during a calender month is given below : Total working hours = 400 Total maintenance hours = 100 Total hours of actual work = 240 The percentage utilization of the equipment is ______________ %. 80. A company produces two types of toys : P and Q. Production time of Q is twice that of P and the company has a maximum of 2000 time units per day. The supply of raw material is just
sufficient to produce 1500 toys (of any type) per day. Toy type Q requires an electric switch which is available @ 600 pieces per day only. The company makes a profit of Rs 3 and Rs 5 on type P and Q respectively. For maximization of profits, the daily production quantities of P and Q toys should respectively be
81. A curve y = x ≤ 3 is
is allowed to revolve around x axis. The volume of solid of revolution for 2 ≤
82. A complex number is defined as z = The simplified value of z is approximately
83. The integral
to
where i is the square root of negative unity.
is evaluated by changing the order of integration, that leads
The value/expression for q and s are respectively
84. The vectors from origin to the points A and B are area of the triangle OAB _________ unit2. (where O is origin)
respectively. The
85. In a lottery, 20 tickets are drawn at a time out of 50 tickets numbered from 1 to 50. The expected value of the sum of the numbers on the tickets drawn is ____________.
86. The solution of the differential equation
87. A function f (x) is defined as For f (x) density function the value of A must be
to be a valid probability
88. If a triangle ABC has vertex points A(0, 0), B(1, 0) and C(0, 1), then the value of integral evaluated over the triangle is 89. If the probability of a bad reaction from a certain injection is 0.001, then the probability that out of 2000 individuals more than two will get a bad reaction is 90. If a force displaces a particle in the xy plane from (0, 0) to (1, 4) along a 2 curve y = 4x , then the work done by the force is
91. A player tosses two fair coins at a time. He wins Rs 2 if 2 heads occur and Rs 1 if 1 head occurs. On the other hand, he loses Rs 3 if no heads occur. If the player plays for 100 times, then the probable amount he will get is _________ `.
92. If the residue of the function
at its pole is
then the value of p is ______.
93. A motor of 50 W power rotates a solid shaft AB at 500 rad/s. The weight density of the shaft AB is 12 N/m3. The maximum normal stress induced in shaft is __________ Pa.
94. The overhanging beam ABC carries a concentrated load P at end C the displacement of the beam at C, is ___________m.
95. A sphere of diameter 5 m is subjected to a uniform pressure P = 250 MPa on all directions as shown and the Young’s modulus of sphere is E = 200 GPa. The bulk modulus of the material of sphere is
96. An elastomeric bearing pad is subjected to a shear force during a static loading test. The pad has dimensions a = 150 mm and b = 225 mm and thickness t = 55 mm. The lateral
displacement of the top plate with respect to the bottom plate is 14 mm under a load P = 16 kN. The shear modulus of elasticity G of the elastomer is approximately.
97. A rod [Young’s modulus 200 N/m2 and Poisson’s ratio 0.4] of length 4 m is suspended from the ceiling by one of its ends. The weight density of the rod is 1.2 N/m 3. The relative increment of its volume ΔV/V is ________ × 10–3. 98. An incompressible fluid is flowing through a contraction section of length L and has a 1–D (x–direction) steady state velocity distribution, . If u0 = 2m/s and L = 3 m, the 2 convective acceleration (in m/s ) of the fluid at L is ___________. 99. In an orifice meter, if the pressure drop across the orifice is overestimated by 5% then the PERCENTAGE error in the measured flow rate is ______________. 100. A turbine develops 3 MW when running at a speed of 140 rpm and under a head of 10 m. The specific speed of the turbine in S.I. unit is ______________. 101. A large airship of volume V contain helium under standard atmosphere condition (T = 15°C, p = 101.325 kPa). The density of the helium is ___________ kg/m3 102. A pump draws oil (specific gravity 0.8) from a storage tank and discharges it to an overhead tank. The mechanical energy delivered by the pump to the fluid is 50 J/kg. The velocities at the suction and the discharge points of the pump are 1 m/s and 7 m/s, respectively. Neglecting friction losses and assuming kinetic energy correction factor to be unity, the pressure developed by the pump (in kN/m2) 103. A liquid is flowing through the following piping network. The length of pipe sections P, Q, R and S shown in the schematic are equal. The diameters of the sections P and R are equal and the diameter of the sections Q is twice that of S. The flow is steady and laminar. Neglecting curvature and entrance effects, the ratio of the volumetric flow rate in the pipe section Q to that in S is ___________.
104. A liquid flowing in a pipe a head loss of 2 m in pipe length of 10 m. The Reynolds number of the flow is 100. If the flow rate is doubled and all other properties remains the same, the head loss is ________m. 105. A turbine is to operate under a head of 25 m at 200 rpm. The available discharge is 9 3 m /s. Assuming overall efficiency of 90%. The power generated by the turbine under the head of 20 m is _________MW. 106. A steam power station uses the following property table to evaluate the various parameter regarding power plant performance.
Steam rate = 200 TPH The overall heat transfer coefficient for condenser tubes is 3200 W/m 2K and inlet and outlet temperature of cooling water is 30°C and 40°C respectively. The area of tubes of condenser is 107. The figure shows a paddle wheel coupled with an agitator submerged in a water tank placed in a ice bath at 0°C. The thickness of the tank walls is 2 mm and with thermal conductivity 0.5 W/m°C. The surface area of tank in contact with water is 0.05 m 2. It is found that in steady state the block goes down with constant speed of 0.1 m/s and the temperature of water in the tank remains constant at 1°C. The mass of block is
108. For a cylinder of radius 10 mm the temperature distribution in radial direction is given by T = 2r 2 – 4r + 5 where r (in m) is measured from centre. The cylinder is placed in ambient at 20°C and heat transfer coefficient of 8.49 W/m 2K. If the thermal conductivity of cylinder is 30 W/mK. The wall temperature of cylinder is 109. A wall of 0.5 m thickness is to be constructed from a material which has an average thermal conductivity of 1.4 W/mK. The wall is to be insulated with a material having an
average thermal conductivity of 0.35 W/mK so that the heat loss per square metre will not exceed 1450 W. Assuming that the inner and outer surface temperature are 1200°C and 15°C respectively. The thickness of insulation required is ______________ metre. 110. One end of a thermally black metallic rod of length 10 cm is inserted in a furnace whose temperature is 827°C. The curved surface of the rod is insulated. The room temperature is 27°C. When the steady state is attained the temperature of the other end of rod is 702°C. The thermal conductivity of the rod is______ W/mK.
111. Oil at 150°C flows slowly through a long thin walled pipe of 30 mm inner diameter. The pipe is suspended in a room for which the air temperature is 20°C and convection coefficient at the outer tube surface is 11 W/m 2K. The heat lost per unit length of tube is ___________W. 112. An enclosure 1 × 2 × 4 consists of three surfaces. Flat surface at the bottom 1 × 2, A1 = 2 2 m , flat surface at the top 1 × 2 m, A2 = 2 m2 and all vertical surfaces taken together A3 = 24 m2. All the surfaces are flat and A1 is parallel to A2. Shape factor F1–2 = 0.035. The ratio of F13 and F3–2 will be _________. 113. Water enters a very long tube having an inner diameter of 0.01 m with velocity and temperature 0.01 m/s and 30°C respectively. The average difference between the tube inner surface and bulk mean temperature of water is 10°C. The value of constant and uniform heat flux imposed on the tube is ___________ W/m 2.[Take the properties of water at mean bulk emperature of 40°C as ρ = 990 kg/m3, ν = 0.65 × 10–6m2/s; c = 4178 J/kgK, k = 0.62 W/mK; Pr = 4.3]. 114. A body emits maximum energy at 4253 Å and the same body at some other temperature emits maximum energy at 2342Å. The ratio of the maximum energy radiated by the body in a short wavelength range is 115. A hot cylinder ingot of 50 mm diameter and 200 mm long is taken out from the furnace at 800°C and dipped in water till its temperature falls to 100°C, then the Biot number will be [Take k = 60 W/m°C, h = 200 W/m2°C] 116. A metal plate of 4 mm thickness and having k = 95.5 W/m°C is exposed to gas temperature of 100°C at one end and cooling at 25°C by water on the other side. If the heat transfer coefficient of gas and water are 14500 W/m 2°C and 2250 W/m2°C respectively. The temperature on gas side of plate is
117. Air at 20°C flows past a 250 mm long plates at a velocity of 45 m/s. If the surface of the plate is maintained at 300°C. Take properties of air as: k = 0.03638 W/m-K, α = 44.10 × 10–6 m2/s, Pr = 0.682. The heat transferred from the entire plate length to air assuming unit width of the plate will be __________ W. 118. Consider a 3m × 3m × 3m cubical furnace. The base surface is black (1) and has a temperature of 550 K. The radiosities for the top (2) and side (3) surfaces are calculated to be 7500 W/m2 and 3200 W/m2, respectively. The net rate of radiation heat transfer to the bottom surface is __________ kW. (Take F12 = 0.2 and F13 = 0.8) 119. Molten aluminium was poured in a sand mold and the thickness of solid skin formed after 10 sec and 20 sec were found to be 2 mm and 4 mm respectively, then the thickness of the solid skin at the end of 80 sec after pouring will be 120. In an interchangeable assembly, a shaft of mm diameter and a hole of mm diameter form a mating pair. In the worst assembly condition, clearance between them will be. 121. A vernier scale consist of 25 divisions on 12 mm spacing and the main scale has 24 divisions on 12 mm then least count of vernier scale will be _________ mm. 122. In orthogonal machining with a cutting tool having 10° rake angle, chip thickness is measured to be 0.4 mm, the uncut thickness being 0.15 mm, then the magnitude of the shear strain will be _________. 123. A 600 mm long shaft has a 160 mm tapered step at the middle with 4° included angle. The tail-stock offset required to produce this tapper on lathe would be __________ mm. 124. In a conventional milling operation, if depth of cut and diameter of cutter both gets thrice, then percentage change in maximum uncut thickness will be __________ . 125. An engine produces 12 kW brake power while working with a brake thermal efficiency of 28%. The calorific value of the fuel used is 40,000 kJ/kg. The fuel consumption in kg/hour is __________. 126. In a power plant, water (ρ = 1000 kg/m3) is pumped from 90 kPa to 2.5 MPa. The pump has an isentropic efficiency of 0.85. Assuming that the temperature of the water remains the same, the specific work (in kJ/kg) supplied to the pump is _____________. Consider the following statements about a two-stroke engine: P It has higher thermal efficiency. Q : It has higher mechanical efficiency. R : It is much easier to start a two-stroke engine than a four stroke engine. S : For the same power developed, it is much lighter, less bulky and occupies less floor area than a four-stroke engine Q,R,S. Select the CORRECT statements? 1.Mechanical efficiency of an I.C. engine as compared to gas turbine is higher. 2. Thermal efficiency of a diesel engine plant as compared to gas turbine plant is higher. 3. Thermal efficiency of petrol engine as compared to diesel engine is lower 2,3
127. In a Morse test for a 2-cylinder, 2-stroke SI engine, the brake power was 10 kW whereas the brake power of individual cylinder with spark cut-off were 4.75 kW and 4 kW respectively. The mechanical efficiency of the engine is 128. The engine of a car has four cylinders of 70 mm bore and 75 mm stroke. The compression ratio is 8. The cubic capacity of the engine and the clearance volume of each cylinder are ______ , ______ respectively. 129. A gas turbine plant operates in an air-standard Brayton cycle between the temperature limits of 27°C and 800°C. The ratio of Carnot efficiency to the Brayton cycle efficiency for maximum work is 130. An automobile engine operate at a fuel-air ratio of 0.06, volumetric efficiency of 92% and indicated thermal efficiency of 32%. The calorific value of the fuel is 50000 kJ/kg and density of air at intake is 1.2 kg/m 3, the indicated mean effective pressure (in MPa) for the engine is __________. 131. A power station produces 500 MW of power. The plant thermal efficiency is 33%. The rise of cooling water temperature is to be restricted to 5°C. The rate of cooling water flow required in tons per hour is _____________ × 105. (Take specific heat of the water is 4.2 kJ/kgK.) 132. If the true stress strain curve of a ductile material is represented by the equation σ = 0.3 800ε , the ultimate tensile strength (engineering) will be __________ MPa 133. A turbocharged four-stroke direct injection diesel engine has a displacement volume of 0.0259 m3. The engine has an output of 950 kW at 2200 rpm. The mean effective pressure (in MPa) is ________. 134. In a multiple disc clutch, if there are 6 discs on the driving shaft and 5 discs on driven shaft, the number of pair of contact surfaces will be equal to 135. If helix angle (α) is 15° and circular pitch (Pc) is 30 mm then axial pitch of helical gear is _____ mm 136. The maximum tension in belt is 800 N, angle of wrap is 50° in tension ratio is 2 as shown in figure, then braking effort required in the simple band brake, when drum is rotating in clockwise direction is
137. A band brake acts on the circumference of the drum of 300 mm diameter and half of the circumference of the drum is covered by the band. If the band provides a braking torque of 250 N, the tension in the tight side is (Take μ = 0.3) 138.
Two plate are jointed a shown in the figure.
The maximum tensile and shear stresses are 80 N/mm2 and 60 N/mm2 respectively. The plate is 70 mm wide and 15 mm thick. What will be the value of L if the total load carried by the joint is 80 kN? 139. A forged steel bar of 50 mm diameter, is subjected to a reversed bending stress of 250 2 N/mm . The bar is made of steel 40 C8 (Sut = 600 N/mm2) and the corrected endurance limit of the bar is 101 N/mm2, then life of the steel bar will be ______cycles. 140. A pinion has 15 teeth and module of 8 mm. The gear ratio is 10 : 1 and the pressure angle is 22.5°. The pinion transmits 500 kW at 1800 rpm then normal load on the tooth will be ________ kN. 141. A shaft rotating at constant speed is subjected to variable load. The bearing supporting the shaft are subjected to stationary equivalent radial load of 3 kN for 10% of the time, 2 kN for 20% of the time, 1 kN for 30% of the time and no load for the remaining time of cycle. If the total life expectancy of the bearing is 37 millions revolutions at 90% reliability, the dynamic load rating of the ball bearing is___________kN. 142. A vibrating system shown in figure with a mass 40 kg, stiffness 18 kN/m and damper having damping coefficient 54 N-s/m, when an exciting force of magnitude 64 sin(37.7 t ) is acting, what would be the frequency of vibrations in Hz. [Approx]
143. A cam operates a knife edge follower having a lift of 30 mm. The cam raises the follower with SHM for 180° of rotation followed by a period of dwell for 60°. The follower descends for next 100° rotation of cam with uniform velocity, again followed by a dwell
period.The cam rotates at 120 rpm and has a least radius of 20 mm. The maximum acceleration of follower during lift will be __________ m/s2. 144. One of the driving axles of a locomotive with its two wheels has moment of inertia of 350 kg-m2. The wheels are of 1.85 m diameter. The distance between the planes of the wheels is 1.5 m. When travelling at 100 km/hr the locomotive passes over a defective rail which causes the right hand wheel to fall 12 mm and rise again in total time of 0.1 sec, the vertical movement of wheel being S.H.M. What is the maximum gyroscopic torque when the wheel is falling? 145. Two involute gears in a mesh have a velocity ratio of 3. The arc of approach is not to be less than the circular pitch when the pinion is the driver. The pressure angle of the involute teeth is 20°. The least number of teeth on each gear is 146. In a spring controlled governor the curve of controlling force is a straight line. When balls are 35 cm apart the controlling force is 1100 N and when 20 cm apart it is 550 N. To make the governor isochronous, the required initial tension on the spring would be _________ N. 147. The torsional pendulum with a disc of MOI 0.05 kg-m 2 immersed in a viscous fluid as shown in diagram during vibrations of pendulum, the observed amplitudes on the same side of neutral axis for successive cycles are could to decay 50% of initial value. The damping factor will be ___________.
148. A metal block of mass 1 kg and heat capacity C J/K at T1 K is dropped from a height Z m into a lake at T2 K. (T1 > T2). What is the entropy change of the universe during the process? 149. A fully charged battery gradually discharges while lying in a room at constant temperature. During discharging, it loses 1020 kJ to the environment. The battery is then recharged slowly to its initial state. The charging process consumes 0.7 kWh of electricity. What is the heat transfer during the charging process? 150. One kilogram of air is in a piston-cylinder apparatus that can only exchange heat with a reservoir at 300 K. Initially this air is at 100 kPa and 27°C. It is then compressed to 250 kPa and 27°C. The process is
151. A 2m × 5m × 10m room is to be heated by a resistance heater. It is desired that the resistance heater be able to raise the air temperature in the room from 10°C to 25°C within 15 minutes. Assuming no heat losses from the room and an atmospheric pressure of 100 kPa, the required power of the resistance heater is ___________ kW. 152. A mass of air is stirred by a paddle wheel in an insulated constant volume tank. The velocities due to stirring make a negligible contribution to the internal energy of the air. Air flows at through a small valve in the tank at the rate of 0.9 kg/h to keep the temperature in the tank constant. At a certain instant, the pressure and tank volume are found to be 1 MPa and 0.15 m3 respectively. If the power to the paddle is 0.2 kW, the temperature of air in the tank is ____________ °C. 153. The specific exergy of air for a state at 2 bar, 600 K when surrounding are at 1 bar, 300 K is ______kJ/kg. (Take cp = 1 kJ/kgK and R = 0.3 kJ/kgK) 154. A power plant operates at 30% efficiency during summer when the sea water used for cooling is at 25°C. The plant uses 350°C steam to drive turbines. If the plant’s efficiency changes in the same proportion to ideal efficiency, the plant efficiency in winters when the sea water is 10°C is: 155. A reversible heat engine operates with three thermal reservoirs and delivers 50 kW power. The engine absorbs 1000 kJ/s from a reservoir at 600 K. The temperature of the other reservoirs are 400 K and 300 K. The thermal efficiency (in %) of the engine is ___________. 156. Air at 3 bar and 400°C is contained in a cylinder fitted with a piston and a set of stops as shown in the figure. The air is cooled as a result of heat transfer to the surroundings making the piston reach the stops. The pressure of air when its temperature becomes equal to room temperature of 20°C is ______bar.
157. A household refrigerator is maintained at a temperature of 2°C. Each time the door opens, warm food is placed inside introducing an average heat of 400 kJ. The refrigerator operates at 20% of the ideal COP. The monthly bill at the rate of Rs. 3 per kWhr is Rs. 200. If the atmosphere is at 27°C, the number of times in a day the door is opened is ________
158. One kg of steam expands following the law pvn = constant. Initial pressure of steam and dryness fraction are 10.5 bar and 0.9 respectively. The final pressure and volume are 1.05 bar and 0.679 m3. If the density of saturated liquid and saturated vapor at 10.5 bar are 990 kg/m3 and 5.15 kg/m3 respectively, the index n of expansion is __________. 159. The sales units, selling price per unit and variable cost per unit for A, B and C are indicated in the table below.
Taking fixed cost of Rs. 40,000 the break even sales is ___________. 160. A contractor has to supply 5000 bearings per day to an automobile manufacturer. He finds that, when he starts a production run, he can produce 15000 bearings per day. The cost of holding a bearing in stock per one year is Rs. 2 and the setup cost of a production run is Rs. 1,100. How frequently should the production run be made? (Take number of working days in a year = 300) 161. An auto company manufactures cars and trucks. Each vehicle must be processed in the paint shop and body assembly shop. If the paint shop were only painting trucks, then 40 per day could be painted. If the paint shop were only painting cars, then 60 per day could be painted. If the body shop were only producing cars, then it could process 50 per day. If the body shop were only producing trucks, then it could process 50 per day. Each truck contributes $300 to profit, and each car contributes $200 to profit. What will be the maximum profits of the company? 162. Patients arrive at a clinic at the rate of 4 per hour and are examined at the rate of 5 per hour. If there is a restriction of 10 people, the probability (in percentage) that a patient is forced to leave without joining the queue is __________. 163. If A is a 3 rowed square matrix such that its determinant is|A|, then |adj(adj A2)| is equal to 164.
The orthogonal trajectories of the family of curves y = cxk are given by
165. The maximum distance of the point (3, 4, 12) from the point which lies on the sphere 2 2 x + y + z2 = 4 is _________ units. 166.
If z =
up till n times.
167. The value of the integral is defined by | z | = 4. The value of k is ___________.
is evaluated over the curve c which
168. Which of the following apparatus will independently measure the dynamic pressure of the fluid flowing in the pipe?
169. A 15 kg block slides down an incline of 30° on a 0.1 mm film of SAE oil μ = 8.14 × –2 10 Pas. Area of contact is 0.25 m2. The terminal velocity is
170. A smooth pipe 30 cm in diameter and 100 m long has a flush entrance and submerged discharge. The velocity is 3 m/s. If the fluid is water at 15°C the total loss of head is _________ m. Take f = 0.0122. 171. In a Pelton wheel, the bucket angle is 165° and the ratio of peripheral velocity to jet velocity is 0.46. The hydraulic efficiency is __________%. 172. In a Pelton wheel installation the effective head is 180 m and Euler head is 168 m. The turbine develops 3750 kW shaft power and 4475 kW power is developed by the runner. The overall efficiency is ______%. 173. In a Pelton wheel, the diameter of the wheel is 2 m and the angle of deflection is 162°. The jet diameter is 165 mm and the pressure behind the nozzle is 1000 kPa. The hydraulic efficiency when the wheel rotates at 320 rpm is 174.
An inward flow turbine with radial discharge works under a head of 8 m and the
peripheral velocity at inlet is and flow velocity is efficiency is 85%, the velocity of whirl at inlet is __________ m/s.
If the hydraulic
175. Saturated steam at atmospheric pressure is available on a plate maintained at T1°C by circulating cooling water through the other side. The rate of dripping of the condensate of the plate is x when the plate is vertical. When the plate is tilted at an angle of 45°, the rate of condensate dropping becomes.
176. Two horizontal steam mains with diameters d1 and d2 are laid in a boiler house such that any mutual heat effect is precluded. The mains are at the same surface temperature. What is the ratio of heat transfer coefficient h1/h2 for one meter length of the mains? 177. When modelling unsteady conduction in a semi-infinite slab with convection at the surface, the appropriate length scale is: 178. Heat flows along the axis of a solid which has the shape of a truncated cone with circumferential surface insulated as shown in the figure. The base plane (at x = 0) is at 400°C and the area of section at distance x from base of the cone is given by: 179.
A = 1 – 2.5x (where x is in meters)
180. If the plane at x =0.2 m is maintained at 50°C, the temperature gradient at x = 0 is __________ °C/m.
(Take thermal conductivity of solid material = 2 W/mK) 181. Two identical heated plates are exposed to still air, thus generating natural convection. One plate is vertical with a Grashoff number of Gr 1, while the other faces down at an angle of 45 degrees and has a Grashof number of Gr2. The ratio Gr2/Gr1 is ___________. 182. A long, circular aluminium rod attached at one end to a heated wall transfer heat through convection to a cold surrounding fluid. If the diameter of the rod is tripled, the percentage change in the rate of heat removal is ________. 183. Consider turbulent flow of a fluid through an isothermal square channel. The percentage change in the rate of heat transfer when the free-stream velocity is tripled is ____________. 184. A 5 cm diameter, 1 m long shown in the figure is having its lower circular face grinded smooth. The remainder of the rod is exposed to 30°C room air and a surface coefficient heat transfer equal to 7 w/m 2K exists between the rod surface and the room air. The grinder dissipates mechanical energy at the rate of 20 W. If the thermal conductivity of rod material is 40 W/mK, what is the temperature of the rod at the point where the grinding is taking place?
185. A solid aluminium sphere of diameter D and emissivity ε, initially at a high temperature is cooled by convection and radiation in a chamber having walls at lower temperature. Convective cooling is achieved with a gas passing through the chamber at T∞ temperature resulting in a convective heat transfer coefficient of h. Taking the emissivity of aluminium as ε and the density and specific heat as ρ and c respectively, the variation of sphere temperature with time during cooling process can be predicted by which of the following differential equations? 186. A horizontal semi-transparent plate is uniformly irradiated from above and below while air at T = 300 K flows over the top and bottom surfaces, providing a uniform convection heat transfer coefficient of h = 40 W/m2K. The total hemispherical absorptivity of the plate to the irradiation is 0.4. Under steady state conditions, measurements made with radiation detector above the top surface indicate a radiosity (which includes transmission, reflection and emission) of 5000 W/m 2, while the plate is at a uniform temperature of 350 K. What is the emissivity of the plate? 187.
The temperature variation within a slab of thickness 50 cm is given by the relation: t x = 100 + 200x – 200x2
Where t is in °C and x is the distance measured from one face in meters. Taking unit area normal to the direction of heat transfer, the heat generation rate per unit volume inside the slab is __________ W. (Take thermal conductivity of slab material as 50 W/mK) 188. Two long copper rods of diameter D = 1 cm are soldered together end to end with solder having melting point of 650°C. The rods are exposed to air at 25°C with a convection heat transfer coefficient of 10 W/m 2K. The minimum electrical power input needed for the soldering to occur is _______ W. (Thermal conductivity of copper = 379 W/mK). 189. A diffusely emitting surface is exposed to a radiant source causing the irradiation on the surface to be 1000 W/m2. The intensity of emission is 143 W/m 2·sr and the reflectivity of the surface is 0.8. The net heat flux to the surface by radiation is ______________ W/m 2. 190. A 10 mm diameter mild steel sphere (k = 45 W/mK) initially at temperature of 500°C is exposed to air flow at temperature 25°C resulting in convective heat transfer coefficient h = 100 W/m2K. The properties of mild steel are Density=7850 kg/m3, Specific heat = 450 J/kgK, Thermal diffusivity=1.2×10–5m2/s The total energy transferred from the sphere during the first one minute is __________ W.
191. A cold storage consists of a cubical chamber of dimension 2m × 2m × 2m, maintained at 10°C inside temperature. The outside wall temperature is 35°C. The top and side walls are covered by a low conducting insulation with thermal conductivity k = 0.06 W/mK. There is no loss of heat from the bottom. If the heat loss through the top and side walls is to be restricted to 500 W, the minimum thickness of insulation required is _____________ mm. Which one of the following statement is not correct? End milling cutter are combination of both slab milling and face milling operation. When milling is performed on two surfaces simultaneously, it is known as straddle milling. Producing screw thread over a lathe is known as thread chasing. Tapping is a process of creating internal threads. 192. In sand casting of hollow part of zinc, a cylindrical core of diameter 130 mm and height 200 mm is placed inside the mould cavity. The densities of core material and zinc are 1500 kg/m3 and 12000 kg/m3 respectively. The net force that tends to lift the core during pouring of molten metal will be_____ N. 193. A 20 mm wide and 4 mm thick C20 steel sheet is required to be bent at 60° at bend radius 10 mm. Then the bend allowance will be _____________mm. 194. A spectrometer gives the following reading when used to measure the angle of prism. Main scale reading = 58.5 degree. Vernier scale reading = 9 division Given that 1 division on main scale corresponds to 0.5 degree. Total division on the vernier scale is 30 and match with 29 divisions of the main scale. The angle of prism from the above data is: 195. Consider the following data pertaining to a typical surface grinding operation: Wheel diameter = 160mm Cutting depth = 0.04 mm Workpiece velocity = 400 mm/s Grain velocity = 25 m/s What is the undeformed chip length? 196. What is the percentage of CO during the combustion of ethene (C 2H4) in the oxygen atmosphere when 2.5 moles of oxygen is available? 197. A four stroke single cylinder engine with brake mean effective presssure of 5.5 bar produces 100 kW power. What is the swept volume (in litres) if the engine speed is 2400 rpm? 198. For BCC iron, the interplaner spacing is 0.1013 nm. What is the diffraction angle for the (220) set of planes if the lattice parameter for iron is 0.2866 nm, monochromatic radiation having a wavelength of 0.1790 nm is used and order of reflection is 1? 199. In an open cycle gas turbine, with regeneration air enters the compressor at a pressure of 1 bar and leaves at a temperature of 350 K. The maximum temperature in the cycle is 1050K. Air flowing at the rate of 10 kg/s through the cycle expands isentropically in the turbine attaining an exhaust temperature of 750 K. If the heat supplied during combustion process is 5500 kW, the effectiveness of the regenerator is ____________ percent. 200. The stroke and bore of a two stroke S.I. engine are 150 mm and 100 mm respectively. The compression ratio is 8.5. If the specific heat ratio is 1.4, the clearance volume is __________ cm3. 201. A steam turbine plant is equipped with a single regenerative feedwater. Steam at an initial pressure of 16 bar with an enthalpy of 3000 kJ/kg enters the turbine. It is extracted at 2 bar where its enthalpy is 2600 kJ/kg. Exhaust steam comes out at a pressure of 0.05 bar and enthalpy 2115 kJ/kg. If the thermal efficiency of the cycle is 34%, the condenser duty with
regeneration is (The enthalpy of saturated liquid at 2 bar and at 0.05 bar is 505 kJ/kg and 140 kJ/kg respectively) 202. In an ideal Brayton cycle, atmospheric air at 300 K enters the compressor at the rate of 3.78 × 105 kg/h attaining a maximum temperature of 1500 K. If heat is supplied to the air at the rate of 120 MW, the back work ratio is 203. In an engine working on dual combustion cycle, the pressure at the beginning of the compression is 1 bar. The heat supplied per kg of air is 1500 kJ, half of which is supplied at constant volume and half at constant pressure. The maximum pressure in the cycle is 72 bar. If the compression ratio is 13 : 1, what is the temperature of the air at the beginning of compression? (Take cV = 0.7 kJ/kgK and γ = 1.4) 204. In an air standard Otto cycle, the ratio of maximum and minimum temperatures is 6. The compression ratio is 5.2. What is the maximum to minimum pressure ratio in the cycle? 205. A six cylinder, four stroke spark ignition engine of 10 cm bore and 15 cm stroke gives a brake specific fuel consumption of 0.5 kg/kWh with a mean effective pressure of 5.4 bar. The engine speed is 4800 rpm. What is the rate of fuel consumption in kg/min? 206. An open cycle gas turbine plant operates with a pressure ratio of 4.5 while using 81 kg/min of air and1.5 kg/min of fuel. The plant gives a net output of 250 kW when 220 kW is needed to drive the compressor. Air enters the compressor at 1 bar and 15°C and combustion gases enters the turbine at 760°C. The specific heats of air and combustion gases are 1.005 kJ/kgK and 1.13 kJ/kgK respectively, the index of compression is 1.4 and the index of expansion is 1.3. The mechanical efficiency for both compressor and turbine is 0.98 each. The isentropic efficiency of the compressor is ____________ percent. 207. Two steam turbines A and B operate with same initial pressure 15 bar and same degree of superheat 80°C. The exhaust pressure in turbine A is 0.1 bar and that in turbine B is 0.03 bar. The exhaust steam rejects 2200 kJ/kg of heat at 0.1 bar and 2000 kJ/kg of heat at 0.03 bar. The enthalpy of steam entering the turbine in both cases is 3039 kJ/kg. Following table is provided.
The reduction in steam consumption due to lower exhaust pressure in turbine B is _________ kg/kWh. 208. A two cylinder, 4 stroke, SI engine develops a maximum barke torque of 120 Nm at 2500 rpm. The brake mean effective pressure at the maximum engine torque point is 700 kPa. If bore is equal to stroke, then the stroke volume will be ________ cc. 209. A spray cooling coil is used to operate under the following conditions: Air inlet = 30°C DBT, 21°C WBT Air outlet = 12°C DBT, 6°C WBT Total air flow rate = 2100 m 3/min
If the chilling water inlet and outlet temperature are 5°C and 15°C. What is the water flow rate through the coil? Properties of moist air from psychrometric chart are as follows :
The following statements are TRUE Low molecular weight refrigerants have high latent heat of vaporization. For saturated state at the inlet to the compressor, a refrigerant having high vapour specific heat may give rise to wet compression. 210. The air in a room is to be conditioned to a temperature of 21°C using a cooling coil having ADP temperature of 12°C. The humidity of saturated air at 12°C is 0.25 kg w.v./kg dry air. The outside air conditions are 30°C DBT, 23° WBT and 0.7 kg w.v./kg d.a. absolute humidity. The moisture content of air being supplied to the room is ____________ kg w.v./kg dry air.
211. An electrical heater heats 0.1 m3/s of air from 15°C and 80% RH to 55°C. The barometric pressure at 15°C is 100 kPa and the saturation pressure is 1.625 kPa. The mass flow rate of dry air through the heater is _____________ kg/s. 212. 0.2 kg/s of moist air at 45°C (DBT) and 10% RH is mixed with 0.3 kg/s of moist air and temperature T°C and a humidity ratio of 0.018 kg w.v./kg d.a. in an adiabatic mixing chamber. After mixing, the mixed air is heated to raise its temperature by 7°C. If the final temperature at the exit of heater is 40°C. The value of T (in °C) is ___________. 213. A cooling tower is used for cooling the condenser water of a refrigeration system. In the tower, air enters at 35°C (DBT) and 24°C (WBT) and leaves at a DBT of 26°C and relative humidity of 95%. The flow rate of air at the inlet to the cooling tower is 19 kg/s. The amount of make-up water required is ___________ g/s. Following data is provided from psychrometric chart.
214. An air conditioned space is maintained at 27°C DBT and 50 percent relative humidity. The ambient conditions are 40°C DBT and 27°C WBT. The space has a sensible heat gain of 14 kW. Air is supplied to the space at 7°C saturated. The following table is provided :
The mass of moist air supplied to the space is ___________ kg/h. 215. A water cooler using R12 refrigerant flowing at the rate of 0.5 kg/s works between 30°C and 9°C. Assuming the volumetric and mechanical efficiency of the compressor to be 90% and 80% respectively, and the mechanical efficiency of motor to be 90%, the power requirement of the motor is _________kW. Given cp(saturated vapour at 30°C) = 0.7 kJ/kgK. The properties of R12 at 30°C and 9°C are:
216. The specific volume of dry air in an air-water vapour mixture having temperature 24°C relative humidity 40% at standard barometric pressure 100 kPa if the saturated air pressure is 20 kPa is Which of the following statements is not correct in the context of structures? In a frame, it is not necessary that all forces are along the members
There is never a need to dismember the structure for finding out the support reactions.
A member of the truss is either in tension or compression An ideal truss, does not transmit moment among the connecting members
217. The number of degrees of freedom of the following mechanism are: (Note that link 5 is parallel and equal in length to link 2 and link 4, also link 1 and link 3 are equal and parallel)
218. A simply supported beam of length 5 m carrier a uniformly increasing load of 800 N/m from one end to 1600 N/m at the other end. The larger of the two reactions is 219. A single stage reciprocating compressor takes in air at 2 bar, 305K. The polytropic compression and expansion follow the relation pv 1.3 = constant and pv1.25 = constant respectively. If the clearance volume is 5% of the swept volume, the maximum theoretical pressure to which the air can be compressed is nearly
220.
Evaluate the integral
221.
The value of integral
, along the straight line from z = 0 to z = 1 + i
222. The standard time of an operation is 20 min. The worker was rated at 120% and the allowances are 25%, the obeserved time (in minutes) would be _________. 223. In an inventory model, the economic lot size is twenty five percent of the quantity ordered at a time. The value of model sensitivity is __________. 224. In a hot working operation the strength constant C = 30000 N/m2 and strain rate sensitivity exponent m = 0.15. The flow stress is ________ kPa at the strain rate of 0.01 s–1. 225. A drilling operation is performed with a 25.4 mm dia twist drill in a steel workpiece. The blind hole depth is 50 mm and point angle is 118°. The cutting speed is 25 m/min and feed = 0.25 mm/rev. The cutting time required to complete the operation is __________ seconds. 226. A disk of dia 40 cm and 5 cm thick is to be casted out of pure aluminium is an open mold operation. Melting temperature of Al = 660°C, pouring temp. = 800°C. Assume that the amount of aluminium heated will be 5% more than that needed to fill the mould cavity. Compute the amount of heat (MJ) added to aluminium starting from room temperature of 25°C. Specific heat of Al(both cold and heated) = 0.88 J/g°C. Heat of fusion = 389.3 J/g. Density Al = 2.70 g/cm3. Give answer in mega joules.
227. A fluid contained in a horizontal piston-cylinder arrangement is agitated by a paddle wheel rotating at a uniform speed of 50 rad/s for 1000 seconds. During the process, the piston of area 0.3m2 slowly moves at a distance of 0.5 m against a pressure of 100 kPa. If net work done by the fluid during the process is 5 kJ, the torque in the motor shaft of the paddle wheels: 1. PM allows formulation of alloys having constituents which have similar properties only. 2. PM metal powders are expensive. 3. Variation in density in a PM component can be troublesome. 4. Only conductive metals can be processed. 2 and 3 228.
Combination of single transverse and double parallel fillet weld joints is shown below:
If the plate thickness is t and allowable shear stress() is half of allowable limits stress(σ), then the maximum load P that the joint can withstand is: 229. A cage weighing 60 kN is attached to the end of a steel wire rope. It is lowered down a mine shaft at am constant velocity of 1 m/s. What is the maximum stress (in MPa) produced in the rope when the supporting drum is suddenly jammed? Free length of the rope at moment of jamming = 15 m, area of cross-section = 25 cm 2, E = 2 × 105 N/mm2. Self weight of rope is neglected. 230. Four masses m1, m2, m3 and m4 200 kg, 300 kg, 240 kg, and 260 kg are rotating in corresponding radius of rotation 0.2 m, 0.15 m, 0.25 m and 0.3 m respectively. The angles between successive masses are 45°, 75° and 135°. What is the magnitude of required balancing mass rotating at the radius of 0.2 m ? 231. A fluid undergoes a reversible adiabatic compression in a device from an initial state of 100 kPa, 0.5 m3 to a final of 500 kPa 0.15 m 3, following the law pV1.3 = constant The change in enthalpy for the process is 232. If X is a variable has a Poisson distribution with a mean λ, λ ≠ 0. Such that P (2) = 9P (4) + 90P (6). Then the value of mean X is 233.
Air at 20°C forms a boundary layer near solid wall, in which the velocity profile is
sinusoidal given by v = vmax
. The boundary layer thickness is 7 mm and peak
velocity is 9 m/s. The shear stress (Pa) in the boundary layer thickness at y = 3.5 mm is _______. (Take μ = 1.81 × 10–5 Ns/m2) 234. A spherical metal (k = 15 W/mK) ball of radius 0.5 m is heated in an oven and then taken out and allowed to cool in ambient of air of temperature 25°C with an average heat transfer coefficient of 20 W/m2. If the temperature profile varies as T(r, t) = 50r 2t + 10r + t + C1, the value of C1,1 second after being taken out of the oven is _________.. [Assume heat transfer to surroundings through convection only] [where t = time, r = radius] 235. A centrifugal compressor running at 10,000 rpm consumes 200 kJ/kg power. The blades are inclined and the slip factor is 0.9. The inlet velocity triangle for the compressor is given below:
The blade speed at outlet is __________ m/s. 236. In a gas turbine power plant, air from atmosphere at 300K temperature is compressed followed by expansion in two turbines of equal pressure ratio with reheat to a maximum cycle temperature of 1200K. The isentropic efficiency of both compressor and turbines are 90%. The pressure ratio across each turbine which gives the optimum specific output is ____________. 237. A series of cold rolling operations are to be used to reduce the thickness of a plate from 50 mm to 25 mm in a reversing two high roll mill. Roll dia = 700 mm, coefficient of friction between rolls and work = 0.15. Minimum number of passes required are ____________. 238. An auditorium has to be air conditioned through a process 1-3 as shown in the figure below. Dehumidification of air takes place through a coil with bypass factor of 0.25 at the rate of 0.0833 kg/s. If the specific volume at inlet of coil is 0.9 m 3/kg, the free air to the circulated is _________ cmm.
239. The rate of arrival of customers at a restaurant follows Poisson distribution with an average time of 5 mintues between 2 customers. The mean service time is 2 minutes. The probability (in percent) that 4 customers arrive in a duration of 20 minutes is ___________. 240. The simplex table given below shows the initial basic feasible solution for the objective function Max Z = 2x1 + 4x2, after the introduction of slack variables S1 and S2.
After the first iteration, the solution of the simplex problem is improved by _______ units. 241. During motoring test of an engine, the generator develops on electric power of 80 kW with an efficiency of 80%. The engine is then stopped and engine shaft connected to a motor is run at the same speed. The motor consumes 15 kW with a motor rating of 90%. The mechanical efficiency of the engine is ____________ percent.
242. Consider a diagonal matrix If the determinant = 25, then the minimum value of the sum of eigen values (λ1, λ2) i.e. (λ1 + λ2) is _________. 243. then is
Given
If ‘s’ represents the portion of sphere
,
__________.
244. A particular system maintained at constant volume has a heat capacity varying with temperature (in K) as Cv = A + 0.01T As the source is cooled from 127°C to the surrounding temperature of 7°C, its entropy reduces by 0.9 kJ/K. What is the value of A? 245. In an air conditioner, a cooling coil with surface temperature equal to ADP temperature is used for refrigeration. The enthalpy difference (in kJ/kg) between the states are indicated in the chart below. The bypass factor for the coil is
What could be the possible modes of failures of the following riveted joint?
I : Tearing of the II: Shearing III: Shearing IV: Crushing of plates or the rivets.
plate
across
of of I, II and IV
the
row the the
of
rivets. rivets. plates.
246. An impulse turbine has equiangular blades with a nozzle exit flow angle of 25°. The maximum value of rotor efficiency considering 15% friction losses along the blades is 247. A Pelton wheel develops 3750 kW under a head by 180 m running at 375 rpm. The velocity ratio is ____________ for the mean bucket wheel diameter of 1.45 m. 248. There is 6 hours duty and a job should take 20 minutes to complete it. But after 6 hours, an operator is able to complete only 15 such jobs. The operator’s performance (in percentage) is ___________. 249. A workpart having a starting height of h = 100 mm is compressed to a final height of 50 mm. During the deformation, the relative speed of the piston compressing the parts is 200 mm/s. The strain rate at height of 75 mm is ___________ s–1. 250. A spherical balloon has a diameter of 0.3 m and contains air at a pressure of 150 kPa. The pressure is proportional to the diameter. A work of 300 kJ is done by the gas resulting in an increase in diameter of the balloon. The increase in diameter is 251. A plane gate of uniform thickness holds back a depth of water as shown. The minimum weight needed to keep the gate closed is approximately
252. A steel rod is subjected to a reversed axial load of 180 kN. Stress concentration factor = 1.0. What is the required diameter the rod (in mm) for the factor of safety = 2? 253. A hollow shaft of outer radius 140 mm and inner radius 125 mm is subjected to an axial force of 68 kN and a torque of 35 kNm. What is the maximum shearing stress in the bar?
254. A simply supported beam is loaded with uniformly increasing load that has value zero at one end and 8000 N/m at other end. The distance of the point of maximum bending moment would be _____________ from the left end support.
255. A simply supported beam is loaded with a concentrated force 80 kN and a couple of 30 kNm. Determine the maximum bending moment in the beam.
256. The cross-section of the beam is as shown in figure below and the allowable working stress in tension as well as compression is 600 MPa, determine the value of ‘b’ in cm.
257. Water flows through a 1 m long stainless steel tube in a boiler with a heat transfer coefficient of 700 W/m2K. The inner and outer diameter of the tube are 1 cm and 1.4 cm respectively. The convective heat transfer coefficient at the outer surface of the tube is 7200 W/m2K. Considering fouling only on the inner surface of the tube, the overall heat transfer coefficient based on the inner surface area per unit length is 317 W/m 2K. The fouling factor is __________ m2K/kW. 258. Steam turbine is provided with a single stage of regenerative feedwater heating as shown in the schematic diagram below. Using a stage efficiency of 80% for the turbine, the heat rejected in the condenser is ___________ kJ/kg.
259. A refrigeration machine is required to produce ice at 0°C from water at 20°C. The machine has a condenser temperature of 298 K while the evaporator temperature is 268 K. The relative efficiency of the machine is 50% and 6 kg of R–12 refrigerant is circulated through the system per minute. The refrigerant enters the compressor with a dryness fraction of 0.6. Specific heat of water is 4.187 kJ/kgK and the latent heat of ice is 335 kJ/kg. The dryness fraction with which refrigerant will leave the compressor is __________. The table of properties of R–12 is given below:
260.
261. The yearly demand of a product for three consecutive years is found to be 250, 260 and 300. Further forecast is made using regression analysis. The slope of the trend line on demand-year graph which minimizes the forecasting error is __________ 262. A steel ring of internal and external diameters 65 cm and 60 cm and length 5 cm is to be casted out of aluminium. If the shrinking allowance are as given below, the volume of molten metal that must be poured into the mold is ________ cc. Liquid shrinkage allowance = 0.5% Solidification shrinkage = 3% Solid contraction during cooling = 7.2% 263. The change in the expansion ratio of a diesel engine with compression ratio 15, if the fuel cut-off is delayed from 4% to 8% is __________.
264. The value of bounded by y = x2 and y 2 = x, is __________
where ‘C’ is the closed curve of the region
265. A structural frame is shown in the figure, hinged at A and roller supported at D. The total reaction at support D is
Which of the following graphs correctly represents the variation of applied pressure in case of forward extrusion process?
266.
A psychrometric process takes place along constant WBT line as shown in the figure
267. A particle of mass m is moving in a circular path of constant radius r, such that its centripetal acceleration ac is varying with time t as ac = k 2rt 2 (k = constant). What is the power delivered to the particle by the forces acting on it? 268. What is the design stress for a piston rod subjected to reversal of loads as per following data? The surface of the rod is ground and surface finish factor is 0.9. There is no stress concentration. The factor of safety = 2. The endurance limit is σe. 269. A bolt is acted upon by an axial pull of 16 kN and a transverse shear force of 10 kN. What is the diameter (mm) of the bolt by maximum shear stress theory if the allowable shear stress is 50 MPa? 270. Air enters at 1 bar and is compressed to 16 bar at the end of a two stage compressor with temperatures at the inlet of first and second compressor being 27°C and 227°C. The pressure at the exit of first compressor for minimum work is 271. A thin shield of emissivity 0.2(on both sides) is placed between two infinite parallel plates at temperature 127°C and 527°C and reflectivity 0.8 each. The temperature of the shield is __________ K. 272. The network for a project along with activity duration and costs are indicated in the figure below. If the indirect cost is 10 per day, the total cost of completing the project is _________.
273. An assembly line consists of workstations X – Y – Z with processing time per unit 30 min, 15 min and 20 min respectively. The number of workstations X required to completely balance the assembly line is ___________. 274. A rigid tank contains air at 2 bar and 57°C. The pressure is raised by heat transfer from a constant temperature reservoir at 407°C. The surrounding temperature is 27°C. The loss of available energy of air due to heat transfer is In electro discharge machining (EDM), if the thermal conductivity of the tool is high and specific heat of the work piece is low, then the tool wear and material removal rate is expected to be: Low and High A pump is installed in a pipeline, the HGL (Hydraulic grade Line) and EGL (Energy Grade Line) for the fluid flowing left to right, when the pump is in full operation, are correctly represented by
275.
The condition to prevent self locking of the following brake is
276. The crushing stress induced between the plates and the rivet, if the load P on the joint is 48 kN (in MPa)
P = 48 kN, t = 16 mm, d = 25 mm 277. A plate 100 mm wide and 10 mm thick is to be welded to another plate by means of a double parallel fillets. The plates are subjected to a static load of 80 kN.What is the length (in mm) of the weld if the permissible shear stress in the weld does not exceed 55 MPa? Allow 12.5 mm for start/stop. 278. A rigid vessel of volume 0.5 m3 contains an ideal gas at 1 kPa pressure. An extraction pump is used to reduce the pressure inside the vessel. The gas leaves the vessel at a constant volume flow rate of 0.02 m3/min. The time taken to reduce the pressure in the vessel to 0.5 kPa, assuming the temperature of the gas to remain constant is
279.
The value of
where c is the unit circle |z| = 1, is
280. The value of the integral which x + y ≤ 1, is
over the region in the first quadrant for
281. Air at a temperature T∞ flows over a flat plate with a free stream velocity of U∞. The plate is maintained at a constant temperature of Ts. The temperature T of air at any location is given by
where y is the distance measured from plate along its normal and δt is the thermal boundary layer thickness. The hydrodynamic boundary layer thickness δ at the location is ___________ mm.
282. A fire engine pump delivers water to a nozzle at C situated at the end of a 100 mm dia pipe. The velocity at the nozzle is 8.31 m/s and jet diameter is 75 mm. Neglecting major and minor losses the power required to drive the pump is _________ kW.
283. In a double pipe heat exchanger the heat capacity rate of hot fluid is half that of cold fluid and the inlet temperatures of hot and cold fluids are 100°C and 20°C respectively. The ratio of the area of parallel flow heat exchanger to that of counter flow heat exchanger which will give the same hot fluid outlet temperature of 60°C is __________. 284. The velocity diagram for an impulse wheel of diameter 1 m rotating at 4200 rpm is shown below. Assuming an energy loss of 36 percent on the blades, the axial velocity vf2 indicated in the diagram is _____________ m/s.
285.
The h-s diagram for a Rankine cycle is given below
Assuming pump work of 15 kJ/kg, the friction losses in the pump are ________ percent. 286. In a DC arc welding operation, the voltage follow: Varc = 20 + 5l where l is length of arc, which was varied from 5 mm to 7 mm. The arc current was varied from 400A to 500A. The open circuit voltage for the welding operation is ____________ V. 287. Moist air with enthalpy 15 kJ/kg and specific volume 0.9 m 3/ kg enters a chamber at the rate of 90 cmm. The atmospheric pressure is 1 bar. While passing through the chamber air absorbs specific heat at the rate of 40 kW and picks up 36 kg/h of saturated steam of
saturated steam of enthalpy 2400 kJ/kg. The enthalpy of the leaving air is ____________ kJ/kg. 288.
The starting solution of a transportation problem is given as follows
The increase in transportation cost if one unit is supplied from S1 to D2 is ___________ units. 289. In a production house, the maximum level of an inventory item is 100 units and is achieved with gradual replenishment at an effective rate of 200 units per month. The optimum quantity to be ordered each time is 150 units. The number of orders per year to minimize the annual cost would be ________.
290.
The value of K is ___________, where K
291. ir flows steadily through an air compressor at the rate of 1 kg/s. The inlet and exit conditions are shown in the figure below:
If the ratio of inlet pipe diameter to outlet pipe diameter is 2, then the ratio of velocity at inlet to the velocity at outlet is 292.
Two refrigeration cycles are coupled, as shown in the T-s diagram below.
The enthalpies at state points are:
Neglecting any loses, the ratio of mass flow rate of refrigerant through cycle 1 to that through cycle 2 is 293. A centrifugal air compressor delivers 20 kg/s of air consuming 5090 kW of power. The speed of the compressor is 10000 rpm. Slip factor is 0.9 and the power input factor is 1.05. The diameter of the impeller is __________ cm. 294. The temperature profile at a particular location in a thermal boundary layer on a plate at a temperature of 60°C exposed to ambient at 20°C is prescribed by the relation t (y) = 50 – 10y +y2The thermal conductivity of plate material is 20 W/mK. The heat transfer coefficient is ________ W/m2K. 295. A flower vendor buys roses for 1 each and sells them for 3 each. Daily demand has the following distribution
If each day’s demand is independent of the previous day’s, the number of papers to be ordered each day is ________. 296.
The production of ‘A’ depends on B, C, D and E as shown in the structure below:
The inventory in hand for A, C and E are 50 units, 10 units, 20 units respectively. The scheduled receipt for D and E are 10 units, and 40 units respectively. For producing 100 units of A, the order size of E should be of _________ units. 297. The temperature of a steel ring is raised by 150°C in order to fit on a wooden wheel of 1.2 m diameter, then the original diameter of the ring is _____________mm. (α = 12 × 10–6 /°C) 298. In the inversion of raw sugar, the time rate change varies as the amount of raw sugar remaining. After 10 hours, 8000 kg of sugar has been reduced to 800 kg. After 40 hours, the amount of sugar will reduced to ____________ kg. Which of the following reversed loading, having the same value of mean and variable stress, will be most severe for the machine component
299. A journal bearing of a centrifugal pump has the following data: Load on bearing = 20 kN, speed of journal = 900 rpm, viscosity of oil = 0.017 kg/ms. If the diameter of the bearing is 100 mm and its length is 1.6 times the diameter, the bearing modulus is: Which of the following figures correctly represent the variation of bending stress and shear stress (respectively) in a simply loaded I-section beam?
300. A rigid vessel of volume 1.2 m3 contains 2 kg of steam at a pressure of 2 bar. The steam is heated to raise its pressure to 2.5 bar. The internal energy at the end of the process (in kJ/kg) is Use the following table:
301. Air at 25°C flows past a flat plate of width 1 m at 5 m/s velocity. The plate is heated over its entire length to a uniform temperature of 75°C. The drag force (on one side) exerted on the first 50 cm length of the plate is ____________ × 10 –3 N. The thermo-physical properties of air are
302. Water flows at a rate of 170 L/s through a bend meter, shown below. The diameter of the bend is 150 mm and pressure drop is 300 mm of Hg. Resistance coefficient of the bend will be _________.
303. The overall heat transfer coefficient due to convection and radiation for a steam main at 207°C running in a large room at 27°C is 18 W/m 2K. The heat transfer coefficient due to convection, taking emissivity of the pipe surface as 0.7 is __________ W/m2K. 304. In a steam power plant, heat is supplied to the feedwater at the rate of 2500 kJ/kg. The exhaust steam gives up heat at the rate of 1000 kJ/kg. The steam rate through the plant is 4 kg/kWhr. If the generator efficiency is 90%, the thermal efficiency exceeds the brake thermal efficiency by _________ percent. 305. Air enters an axial flow compressor at the rate of 25 kg/s. At the inlet of the first stage, the stagnation pressure and temperature are 1 bar and 300 K respectively. If the power input per stage of the compressor is 502.5 kW, then taking inentropic efficiency of 85%, the number of stages required to deliver air at stagnation pressure of 4 bar is ___________. 306. A medium carbon steel workpiece is turned on a lathe at 50 m/min speed, 0.8 mm/rev feed and 1.5 mm depth of cut. The rate of material removal is _________ mm3/min. 307. Air at 30°C is to be heated and humidified to 40°C DBT and 35°C WBT. It is made to pass through an adiabatic humidifier followed by a heater having surface coil temperature 50°C and a bypass factor 0.4. If the WBT at the exit of humidifier is 20°C, the humidifying efficiency is __________ percent.
308.
The value of a + b is ________ 309. For a system with fixed order quantity, the following parameters for an item are given Annual demand (D) = 50000 units, Unit cost = Rs. 2, Ordering cost = Rs. 15 per order, Holding cost = 12% The past lead times are found to be 10 days, 20 days, 15 days, 15 days, The re-order level is ___________ units. (Take number of working days in a year = 250) 310. During the testing of a 4 cylinder, 4 stroke IC engine, the following data was noted Brake power = 45kW, Mechanical efficiency = 75%, Fuel consumption rate at stoichiometric condition = 12.5 kg/hr, Equivalence ratio = 1.1, Calorific value of fuel = 45000 kJ/kg. The indicated thermal efficiency of the engine is _____________ percent.
311.
The residue of f (z) =
is ______.
Consider the following statements: 1. For elastic materials, stress is a function of strain only. 2. For visco-elastic materials, stress depends not only on strain but also on the rate at which the strain is applied. both 1 and 2 312. What is the reaction at C for the beam pin supported and A and roller supported at C as shown in the figure ?
313. An involute spur gear having 4 mm module and 50 teeth is used to transmit 20 kW at 1200 rpm. Its face width is 20 mm and pressure angle of the tooth is 20°. The minimum
allowable stress for the gear material is 180 MPa. The factor which considers the combined effect of pitch line velocity, inertia of rotating parts, dynamic load and other factors is 2. What is the gear tooth form factor ? Very slow motion of a sphere in a viscous fluid was first analysed by Sir George G. Stokes on the assumption that the inertia forces are negligibly small as compared to the viscous ones. The drag force resisting the motion of the sphere is given by 3πμVd
314. A closed cycle ideal gas turbine plant produces a maximum work of 200 kJ/kg. The maximum temperature attained is 707°C. A fuel of calorific value 20000 kJ/kg is used. The air fuel ratio is _______. (Assume cp = 1 kJ/kgK and ratio of specific heats = 1.4) 315. he general solution of the differential equation 316. A 4 cm diameter object spherical in shape, is initially at 25°C temperature. It is placed in boiling water at 100°C for 30 seconds. The value of Biot number and Fourier’s number for the process can be taken as 0.12 and 5.6 respectively. Assuming lumped heat capacity method to be valid, the temperature of the object after 30 seconds is __________°C. 317. The branch of a bank has only one typist. The typing rate is randomly distributed approximating a Poisson distribution with mean service rate of 9 letters per hour. The letters arrive at a rate of 4 per hour during the entire 8-hour work day. If the typewriter is valued at Rs. 1.50 per hour, the average cost due to waiting on the part of typewriter remaining idle is Rs. __________. 318. The tolerance for the basic dimension in the nominal step of 30 mm to 50 mm and IT9, is ________ μm. 319. A 100 mm diameter cutter having 8 teeth is cutting steel at 50 m/min. The depth of cut is 5 mm and table feed rate is 150 mm/min. The width of the workpiece is 100 mm, then the mean area of crosssection of the chip in a slab milling operation is ____________ mm2. 320. In a three wire inspection of external metric thread of M18 × 2, the measurement over the wire was found to be 18.6 mm. The effective pitch diameter of the thread is ________ mm. 321. A close coiled helical spring made of round steel wire of diameter 8 mm is required to carry a load of 1000 N. If the stiffness of the spring is 10 N/mm and diameter of helix is 80 mm then the number of turns required in the spring is ___________. (Take modulus of rigidity of steel = 82 kN/mm2) 322. If A is a non-singular matrix and the eigen values of A are 0.5, 0.6 and 0.7, then the maximum value of the eigen values of A–1 is _____ 323. The scales are so chosen that a reversible cycle plots clockwise circle on the T-S plane. The minimum and maximum values of the temperature are 305 K and 627 K and the entropy 1.23 kJ/K and 2.85 kJ/K respectively. The cycle efficiency is
Consider the following statements: S: Fluids that posses a linear relationship between shear stress and velocity gradients is called Newtonian fluids. T: A fluid where properties are independent of direction at a given position is called isotropic fluid. U: A fluid whose properties are independent of position is called homogenous fluid. S, T and U are true 324. A bolted joint with 2 bolts each at top and bottom and of equal diameter is shown in the figure below. The yield shear stress of the bolt material is 200 MPa. What is the diameter of the bolts, if they are designed using maximum distortion energy theory of failure ?
325. What is the inclination of resultant stress with normal of plane of maximum shear stress of 20 N/mm2 and resultant stress of 90 N/mm2?
where σ1 and σ2 are major and minor principal stresses respectively? 326. A gear pair consists of two spur wheels each having 40 teeth. The pressure angle is 20° and the circular pitch is 4 cm. If the gear pair is to maintain a minimum contact ratio of 1.5, what is the minimum addendum of the teeth? 327. he suspension system of a two-wheeler can be equated to a single spring mass system with viscous damper connected in series. The mass and spring stiffness are 50 kg and 25 kN/m respectively. For the system to be critically damped, a force of 135 N is exerted. What is the plunger velocity?
328. The thrust on the propeller shaft of an engine is beared by a number of collars of outer diameter 60 cm integral with the shaft of diameter 45 cm. The shaft speed is 120 rpm. A uniform pressure of 0.5 MPa acts on the collar with coefficient of friction 0.05. What is the minimum number of collars required if the power loss due to friction is not to exceed 25 kW? 329. The strain on the surface of an experimental specimen made of pure aluminium (E = 70 GPa, μ = 0.33) were measured by means of strain gauges. The gauge were oriented as shown in the figure and the measured strains were εA = 1100 × 10–6, εB = 1496 × 10–6, and εC = – 39.44 × 10–6. The stress σx in the x-direction, is
330. A long metal tube, 7.5 cm internal diameter and 0.15 cm thick, has closed ends, and is subjected to an internal fluid pressure of 3 MN/m2. If modulus of elasticity of tube is 200 GN/m2 and volumetric strain of tube is 0.727 × 10–3, then what is Poisson’s ratio? 331. Sixteen ice cubes, each with a temperature of –10°C and a volume of 8 mL, are added to 1 L of water at 20°C in an insulated container. What is the equilibrium temperature? Take, (cp)ice = 2.1 kJ/kgK; Latent heat of ice = 330 kJ/kg; Specific volume of ice at –10°C = 0.00109 m3/kg
332.
The value of Integral I =
333. Saturated steam leaves a turbine at a flow rate of 2 kg/s and a pressure of 0.51 bar. The vapor is to be completely conduced to saturated liquid in a shell and tube heat exchanger which uses water as coolant. The water enters the thin walled tube at 15°C and leaves at 55°C. The overall heat transfer coefficient is 200 W/m 2K. After extended operation, fouling causes the overall heat transfer coefficient to decrease to 100 W/m 2K. For the same water inlet temperature and flow rate, the percentage reduction in vapour flow rate required for complete condensation, due to fouling is __________ percent. Properties of water
334. A pressure gauge is installed in front of a valve on a water pipe of diameter is 50 mm. When the valve is closed the gauge reads 6 bar. When the valve is opened, the reading drops to 2 bar. The discharge of water in the pipeline is ________ litre/s. 335. A single slider crank mechanism based reciprocating engine is given. Line of reciprocating of the slider passes through the centre of rotation of the crank shaft. The total axial force on the piston is 2 kN. A torque is 100 Nm is produced on the crank shaft at the
instant when the connecting rod makes an angle of 10° with the line of stroke of piston and the crank is 60° away from inner dead centre position. What is the length of the connecting rod? 336. A venturimeter is to be fitted in a 150 mm diameter pipeline horizontally at a section where the pressure is 100 kN/m2 and the pressure at the throat is 75 kN/m 3 (vacuum). The diameter of throat (in mm) is ___________. Assume that 3% of the differential head is lost between the inlet and the throat. 337. A thin metal plate is exposed to solar radiation. The air and surroundings are at 25°C. The heat transfer coefficient by free convection from upper surface of the plate is 15 W/m 2K. The plate has an absorptivity of 0.4 at the long wavelength. The incident solar radiation intensity is 800 W/m2 and there is negligible heat loss from lower surface. If the measured equilibrium temperature of plate is 60°C, the absorptivity of the plate at solar wavelength is ________. –8 2 4 (Take Stiffen Boltzmann constant = 5.67 × 10 W/m K ) 338. Consider a gas turbine that has a pressure ratio of 6 and operates on the Brayton cycle with regeneration between the temperature limits of 20°C and 900°C. If the specific heat ratio of the working fluid is 1.3, the highest thermal efficiency this gas turbine can have is ______%. 339. A steam turbine plant is supplied with steam at 240°C and superheated to 600°C. The condenser is kept at 45°C. If the steam consumption rate is 3.27 kg/kWh, the boiler pressure exceeds the condenser pressure by _____________ MPa.
340. A vapour compression refrigeration works between pressure limits of 10 bar and 3 bar. The working fluid is dry at the end of compression and there is no undercooling before the expansion valve. If refrigerant flow rate is 10 kg/min, the capacity of the refrigerator (in ton) is ___________. Table for properties of the refrigerant as given below:
341. A stockiest has to supply 400 units of a product every Monday to his customers. He gets the product at Rs. 50 per unit from the manufacturer who charges an ordering cost of Rs.
75 per order. The cost of carrying the inventory is Rs. 3.75 per unit per year. The total daily profit if the item is sold for Rs. 55 per unit is Rs. _________. (Assume 52 week per year) 342. A carbon steel member is being machined at a cutting speed of 0.8 m/s with a tool rake angle and width of cut is 5 mm and uncut chip thickness 0.25 mm respectively. The average value of coefficient of friction between the tool and chip is 0.3 and the yield strength of the material is 400 MPa. The force required for cutting is _________ N. (Assume Lee and Shaffer’s relation) 343. A single cylinder CI engine with a brake thermal efficiency of 30% uses diesel oil having a calorific value of 42000 kJ/kg. If mechanical efficiency of CI engine is 80%, the brake specific fuel consumption (in kg/kWh) is __________.
344.
The value of
Consider the 1. Strength of 2. Young’s modulus 3. Young’s modulus of steel Choose the correct statement(s):
following statements: steel increases with carbon content. of steel increases with carbon content. remains unchanged with variation of carbon content. 1 and 3
345. A journal bearing is loaded with a radial load of 30 kN. The journal diameter and length both are 100 mm and it rotates at 1200 rpm. The heat is dissipated from the surface at the rate of 96 J/m2/s/°C. The bearing housing is 20 times the projected area. If coefficient of friction is 0.003 and room temperature is 35°C, then the surface temperature of the bearings is Across the runner of a reaction turbine, relative velocity increases
346. A two stage reciprocating compressor has an inlet pressure of 1 bar and temperature 300 K. Air after first stage of compression is cooled to a temperature of 400K in an intercooler, maintained at a pressure of 5 bar. What is the delivery pressure ? 347. At what point on the curve y = (cosx – 1) in (0, 2π), the tangent is parallel to x-axis? 348. The cost of holding an item in stock is Rs. 5 per unit and the shortage cost is Rs. 12. If Rs. 4 is the purchasing cost per unit, the optimal level of inventory is ____________. Given below is the probability distribution
349. In the welding process, output current for 25% duty cycle is 220 amp, then the weld output current for 55% duty cycle is __________amp.
350. A mild steel block of width 25 mm is being milled using a straight slab cutter 80 mm diameter with 20 teeth. If the cutter rotates at 35 rpm and depth of cut is 2 mm. When the table feed is 20 mm/min, the value of maximum uncut chip thickness, is ________ μm. 351. An open coiled helical spring with α = 45° is subjected to an axial load W such that shear stress due to twisting moment is 100 MPa, then the bearing stress due to bending moments is _________ MPa. Consider the following statements related to Taylor’s principle: 1. Taylor’s principle can be used for holes and maximum diameter of hole should not exceed the ‘NoGo’ limit of size. 2. Taylor’s principle cannot be used for shafts. 3. Taylor’s principle can be used for shafts and minimum diameter of shaft should not be less than ‘NoGo’ limit of size. 1 and 3 352. A steel drive shaft of 100 mm diameter is transmitting 200 kW at 600 rpm to a machine having same diameter shaft with a CI flange coupling. The permissible shear stress for shaft, bolt and key are 50 MPa, 40 MPa and 30 MPa respectively. The bearing stress for bolt and key are 50 MPa. If the width of the key is 50 mm, what is its thickness? 353.
The turning moment diagram of an engine is shown below:
The speed of the wheel varies between 300 rpm and 360 rpm. What is the crank angle measured from TDC, when the angular acceleration of the wheel is 92.15 rad/s 2? 354. A hydrodynamic bearing supporting a load of 12 kN, has a length of 80 mm. It runs at a speed of 1200 rpm. The radial clearance is 0.05 mm and the minimum oil thickness is 0.01 mm. The viscosity of oil used is 0.30 m Pa-s. If the Sommerfeld number is 0.056, the journal diameter (in mm) is 355. A vibrating system consists of a mass 8 kg, connected to a spring of stiffness 300 N/m and a damper. After 3 cycles, due to damping, the original amplitude is reduced by 80 percent. What is the damping coefficient of the damper (in N-s/m)? 356. An aluminium alloy rod of diameter 12 mm and length 150 mm is subjected to a tensile load of 30 kN along its axis. The Young’s modulus and Poisson’s ratio for aluminium are 60 GPa and 0.3 respectively. 3 The elastic energy per unit volume is approximately (MJ/m ): A simply supported beam has the square cross-section having moment of inertia 1728 mm 4. It carries a uniformly distributed load of intensity 10 N/m. Considering only the top fibre of the beam, the correct representation of the longitudinal variation of the bending stress is
357. A pipe carries a stream of brine with a mass flow rate of 5 kg/s. Due to poor thermal insulation, the brine temperature increases from 250 K at the pipe inlet to 253 K at the exit. What is the irreversibility rate? Neglecting pressure losses. (Take To = 293K and cp = 2.85 kJ/kgK) 358.
The value of integral
is equal to
359. A 5 mm diameter and 10 m long electric wire is tightly wrapped with a 1 mm thick plastic cover where thermal conductivity is 0.1 W/mK. Electrical measurements indicate that a current of 10A passes through the wire and there is a voltage drop 8V. The insulated wire is exposed to a medium at temperature 30°C and the temperature at the interface of the wire and plastic cover in steady operation is 105°C. Keeping the current and voltage drop through the wire constant, the change in the plastic cover thickness (in mm) that gives the minimum interface temperature is ___________ . 360. A thermocouple, the junction of which can be approximated as 6mm diameter sphere is used to measure the temperature of a gas stream. The properties of the junction are ρ = 8500 kg/m3, c = 320 J/kg-K and k = 35 W/m-K. The heat transfer coefficient between the junction and gas is 210 W/m2-K. The time required for the thermocouple to read 90% of the initial temperature difference is ___________ s. 361. A Brayton cycle operates at a pressure ratio which is 75% of the pressure ratio where the degree of regeneration becomes zero. The efficiency of this cycle is 45%. The ratio of maximum to minimum absolute temperature is _________. 362. A Rankine cycle operates between pressures of 80 bar and 0.1 bar. The maximum cycle temperature is 750°C. The steam turbine and condensate pump efficiencies are 0.9 and 0.8 respectively. If the heat added in the boiler is 3500 kJ/kg and the thermal efficiency is 30%, the dryness fraction of steam at the turbine exit is ___________. Relevant steam table is given below.
363. Cylindrical bars of 100 mm diameter and 576 mm length and turned in a single pass operation. The spindle speed used is 144 rpm and the total feed is 0.2 mm/rev. Taylor’s tool life relationship is VT0.75 = 75, where V is the cutting speed (m/min) and T is the tool life (min). The time required to produce one piece is __________ minutes. (Given that the handling time is 4 min, and it takes 3 min to change the tool each time). 364. For a period of 4 hours in a day (8 AM to 12 AM) trains arrive at the yard every 20 minutes but the service time is 42 minutes. If the line capacity of the yard is limited to 5 trains, the probability (in percentage) that the yard is empty is _________.
Four new machines M1, M2, M3 and M4 are to be installed in a machine shop. There are five vacant places A, B, C, D and E available. Because of limited space, machine M 2 cannot be placed at C and M3 cannot be placed at A. Cij, the assignment cost of machine i to place j in rupees is shown below:
The total assignment cost in rupees is _________.
365. The angle, at which a 500 mm diameter regulating wheel, running at 67 m/min, be set to have a workpiece feed rate of 0.3 m/min, is _____________ degree.
Consider the following statements related to forging: 1. Flash is excess material added to stock which flows around parting line.
2. Flash helps in filling of thin 3. Amount of flash depends upon forging force.
ribs
and
bosses
in
upper
die.
1 and 2 366. If the T-beam cross-section shown in the given figure, has bending stress of 30 MPa in top fibre, then the stress in the bottom fibre will be (G is centroid)
367. A solid shaft is welded to a flat plate by a t mm fillet weld. The maximum torque that the joint can sustain is T Nm. If the permissible stress in the weld material is not to exceed τ N/m,2, then which of the following is the correct expression for diameter d of the shaft ? 368.
In a two dimensional stress analysis, the state of stress at a point is as shown below:
What is the value of shear stress, τ ?
The parameters which determine the friction factor for turbulent flow in a rough pipe are: Reynolds number and relative roughness 369. The mean diameter of the blades of an impulse turbine with a single row wheel is 100 cm and the speed is 3000 rpm. The power developed by the turbine is 520 kW. What is the axial thrust if theblades experience a net thrust of 3500 N? 370. The solution of differential equation (D3 + D2 + 4D + 4)y = 0 is
371.
A
linear
programming
problem
is
given
as
follows:
The value of the auxiliary objective function given by the initial basic feasible solution is _________. 372. 5 jobs A, B, C, D and E have arrived at one time to be processed on a single machine. The processing time (in minutes) of each job are indicated below.
Assuming that no new jobs arrive thereafter and using SPT rule for optimal sequence, the average in process inventory is __________ jobs 373. A workpiece of 150 cm length and 40 cm width is machined by planing operation with a feed of 0.3 mm/stroke. The machine tool executes 10 double strokes/min. The planing time for a single pass is ________min. 374. A block brake as shown in figure, provides a braking torque of 360 Nm. The diameter of the brake drum is 300 mm. The coefficient of friction is 0.3. The force (P) to be applied at the end of the lever for the clockwise and counter clockwise rotation of the brake drum respectively is :
375. A beam AB supporting two concentrated load P as shown in figure has a rectangular cross-section of width 100 mm and height 150 mm. The distance from each end of the beam to the nearest load is 0.5 m. If the allowable stress in bending is 11 MPa (for both tension and compression) and the allowable stress in horizontal shear is 1.2 MPa, then the maximum permissible value of Pmax of the load is :
376. In a Whitworth quick return motion mechanism, the distance between the fixed centres is 50 mm. The time taken by the cutting stroke is 2.735 times the time taken by the return stroke. What is the length of the driving crank? 377.
A four bar mechanism is shown in the figure below.
The velocity of point A and B are 3.14 m/s and 2.25 m/s respectively. If the efficiency of the mechanism is 70 percent, the mechanical advantage is 378. A journal bearing of length 250 mm supports a turbine shaft of diameter 200 mm running at 1200 rpm. The lubricant of viscosity 0.02 kg/ms removes heat at the rate of 70 J per minute. If the coefficient of friction for the bearing is 0.01, the bearing can withstand a maximum pressure of 379. A cantilever shaft l m long has a disc of mass W kg at its free end. The Young’s modulus for the shaft material is E N/m2. The frequency of transverse vibrations of the shaft is 1 Hz. Which of the following is the correct expression for diameter d of the shaft? 380. A circular rod of 25 mm diameter carries a pull along a line which is parallel to the centroidal axis, but is displaced from it. If the maximum stress is 20% greater than the mean stress on a section normal to the axis, then the distance of the line of pull from the centroidal axis is: 381. A circular rod of 25 mm diameter carries a pull along a line which is parallel to the centroidal axis, but is displaced from it. If the maximum stress is 20% greater than the mean stress on a section normal to the axis, then the distance of the line of pull from the centroidal axis is 382.
: The specific internal energy of a certain fluid is related as follows:
A system composed of 2 kg of the above fluid expands in a frictionless piston and cylinder machine from and initial state of 1 MPa, 100°C to a final temperature of 30°C. If there is no heat transfer, what is the net work for the process ? 383. A particle moves on the curve x = 2t2, y = t2 – 4t, z = 3t – 5 where t denotes the time in seconds then component of velocity and component of acceleration at time t = 1s in the direction of i + 2j + 2k are respectively 384. It was found during a test in which water flowed with a velocity of 2 m/s through a tube (2.5 cm inner diameter and 6 m long), that the head lost due to friction was 1.5 m of
water. The surface heat transfer coefficient based on Reynolds analogy is _____________ kW/m2K. (Take ρ = 1000 kg/m3, g = 10 m/s2 and cp = 4 kJ/kgK) 385. Consider a water flow between two parallel fixed plates 50 mm apart, as shown in figure. The velocity distribution for the flow is given by u(y) = 120(0.05y – y2)m/s where y is in meters. The dynamic viscosity of water is 1.307 × 10 –3 Ns/m2. The magnitude of the shear stress acting on the bottom plate is ____________ N/m2.
386. A selective coating of black chrome is coated over a solar absorber plate. Incident solar flux on the whole plate is 1200 W/m2. Properties of black chrome Absorptivity = 0.95 for short wave Emissivity = 0.05 for long wave 2 If the absorber plate is at a temperature of 127°C, the radiosity (in W/m ) from the absorber plate is __________. 387. A steam turbine with a boiler efficiency of 90 percent and an overall thermal efficiency of 36 percent gives a net electrical work of 1200 kJ per kg of steam flow rate. The fuel cost per kWh generated in the power plant is Rs.0.85. The LCV and the cost of coal are 30000 kJ/kg and Rs.1500 per ton respectively. If 5% of steam generated is used to cover losses, the specific steam consumption is __________ kg/ kWh. 388. Steam issues from the nozzle of an impulse turbine and impinges the blades with a velocity of 520 m/s. The blade velocity is 300 m/s. The velocity coefficient for the blades is 0.8. The friction losses on the blades per kg of steam flow are 15 kJ. The nozzle angle (in degrees) is ________. 389. In arc welding of a butt joint, the welding speed is to be selected such that highest cooling rate is achieved. Melting efficiency and heat transfer efficiency are 0.5 and 0.7, respectively. The area of the weld cross section is 5 mm ² and the unit energy required to melt the metal is 10 J/mm³. If the welding power is 2 kW, the welding speed will be __________ mm/s. 390. A room contains 35 kg of dry air and 0.5 kg of water vapour. The total pressure and temperature of air in the room are 100 kPa and 25°C respectively. Given that the saturation pressure for water at 25°C is 3.17 kPa, the relative humidity of the air in the room is ___________ %. 391. A dealer supplies the following information with regard to a product Annual demand = 10000 units Ordering cost = Rs. 10 per order
Inventory
carrying cost = 20% of inventory value Price = Rs. 20 per unit Annual cost of back-ordering = 25% of inventory value The maximum quantity of the product to be back-ordered is ___________. 392. The flow stress (in MPa) of a material is given by 0.1 σ = 500ε , where ε is true strain. The Young’s modulus of elasticity of the material is 200 GPa. A block of thickness 100 mm made of this material is compressed to 95 mm thickness and then the load is removed. The final dimension of the block (in mm) is ____________. 393. If x, y and z respectively are in Arithmetic Progression with common difference d . If
the rank of matrix is 2, then the value of k is ________ 394. The area bounded by curve y2 = 9x and line x – y + 2 = 0 is __________. Which of the following is not a characterstic of climb milling (down milling) operation? Chip thickness is maximum at the end of the cut 395. A mild steel shaft of 50 mm diameter is subjected to a bending moment of 1.5 kNm and a torque T. The yield point of steel in tension is 210 MPa. What is the maximum value of torque without causing yielding of the shaft material according to maximum principal stress theory? Which of the following are the advantages of a V-belt drive? 1. It can be used with large centre distance. 2. It has lesser weight per unit length compared to flat belts. 3. It can be operated in either direction i.e. with tight side of the belt at the top or bottom. 4. It can provide high velocity ratio. 5. It provides negligible slip between the belt and the pulley. 3, 4 and 5 396. A thin cylindrical steel shell of diameter 150 mm and wall thickness 3 mm has hemispherical ends. What is the thickness of the hemispherical end? If there is no distortion of the junction under pressure. (Take modulus of elasticity = 200 GPa and Poisson’s ratio = 0.3) 397.
Given below is the velocity triangle of a de Laval turbine with symmetrical blades.
Further it is given that the turbine dissipates no energy due to blade friction. For 900 kg of steam flow per hour through the turbine, what is the tangential force (in N) on the blades? 398. If 1 and 3 are the eigen values of a 2 × 2 square matrix A, then A3 can be written as (I2 denotes identity matrix of second order) 399. For where C is the circle x2 + y2 = 4. The value of f ′(i) is 400. A 1 m diameter steel pipe which is 10 m long lies in a room with its axis horizontal. The ambient air is at a temperature of 17°C and the pipe surface is at 257°C. Assume kinematic viscosity of air as 2 × 10–5 m2/s and Prandtl number as 0.8. The value of Rayleigh number is __________ × 1010. (Take g = 10 m/s2) 401. Water flows through a pipe of diameter 30 cm. The velocity V for the condition shown in the figure below is _________ m/s.
402. The demand for a commodity is 900 units per day. Every time an order is placed, a fixed cost of Rs. 500 is incurred. The holding cost is Rs. 0.10 per unit per day. If the lead time is 15 days, the re-order point is _________ units. 403.
The information regarding jobs to be scheduled through one machine is given below
Scheduling according to the slack time remaining, the mean flow time will be _________ days. 404. The ratio of time of return stroke to time of forward stroke of a shaping machine is 0.6. The stroke is 250 mm and it makes 60 double strokes per minute the velocity of cutting is ____________ m/min. 405. Using direct extrusion process, a round billet of 150 mm length and 75 mm diameter is extruded. Considering an ideal deformation process (no friction and no redundant work), extrusion ratio 5, and average flow stress of material 350 MPa, the extrusion force (in MN) on the ram will be __________. 406. In an arc welding of steel, voltage is 40 V and current is 400 A. The travel speed is 10 mm/s and crosssectional area of the joint is 25 mm 2. Heat required to melt steel is 10 J/mm 3. If the heat transfer efficiency is 0.85, the melting efficiency will be____________percent
407. Two closely coiled helical springs ‘A’ and ‘B’ are equal in all respects but number of turns of spring ‘A’ is half that of spring ‘B’, the ratio of deflections in spring ‘A’ to spring ‘B’ is ___________. 408. A domestic refrigerator is loaded with food and the door closed. During a certain period the machine consumes 1 kWh of energy and the internal energy of the system drops by 5000 kJ. The net heat transfer for the system is 409. A 120 mm wide uniform plate is subjected to a tensile load that has a maximum value of 250 kN and a minimum value of 100 kN. The properties of the plate material are as follows: Endurance limit stress = 225 MPa Yield point stress = 300 MPa Assuming a factor of safety of 1.5, what is the thickness (in mm) of the plate for safe continuous operation? 410. A single cylinder reciprocating engine has speed 480 rpm, stroke 600 mm, mass of reciprocating parts 100 kg, mass of revolving parts at 300 mm radius is 65 kg. If two-third of the reciprocating parts and all the revolving parts are to be balanced, the residual unbalanced force when the crank has rotated 60° from inner dead centre is 411. An electric motor of mass 50 kg running at 1800 rpm is mounted on five springs, each of stiffness 45 kN/m and with negligible damping. The mass of the motor is equally distributed among the five springs. What is the isolation factor of the spring support ? 412. A steam boiler is to be designed for a working pressure of 2.5 MPa with its inside diameter 1.5 m. Rivets of diameter 32 mm are used for longitudinal and circumferential joints. What is the number of rivets required to provide enough strength to the circumferential joint ? The working stresses for steel plates and rivets in shear and crushing are 65 MPa and 120 MPa respectively. 413. A stepped steel shaft of length 1.5 m as shown in the figure, carries two flywheels A and B of mass mA and mB and radius of gyration rA and rB respectively at each of its ends
What is the ratio d2 : d3 if the node is at a distance of 0.5 m from A?
414. A bar of steel 0.4 m long and 50 mm square is in compression under an axial load of 200 kN applied in the direction of its length. Find the change in length (in mm) and volume (in mm3), if all the lateral strain in one direction is prevented by the application of a suitable
compressive [Take E = 200 GPa and μ = 0.25]
stress.
415. A hollow cast iron column whose outside diameter is 200 mm has a thickness of 20mm. It is 4.5 m long and is fixed at both ends. What will be the ratio of Euler’s to Rankine’s critical load ?
416. Air enters a device at 4 MPa and 300°C with a velocity of 150 m/s. The inlet area is 2 10 cm and outlet area is 50 cm2. If the air exits at 0.4 MPa and 100°C, what is the outlet velocity ? 417.
The point in the plane 2x – y + 2z = 16 nearest to the origin is
418. A semi-infinite aluminium cylinder (thermal conductivity = 240 W/mK and thermal diffusivity = 9.8 × 10–5 m2/s) is initially at a uniform temperature of 200°C. It is now placed in water at 15°C where heat transfer takes place by convection with h = 120 W/m2K. The value of Biot number is 0.08. Five minutes after the start of cooling, the Fourier number value is __________. 419. Water flows through a pipe having an inner radius of 10 mm at the rate of 36 kg/hr at 25°C. The viscosity of water at 25°C is 0.001 kg/ms. The Reynolds number of the flow is _______. 420. The inlet angle of runner blades of a Francis turbine is 90°. The blades are so shaped that the tangential component of velocity at blade outlet is zero. The flow velocity remains constant throughout the blade passage and is equal to half of the blade velocity at runner inlet. The blade efficiency of the runner is ___________%. 421. A flat plate 1m × 1m is cooled by air at temperature 15°C flowing past it. The plate surface maintained at a temperature of 75°C, loses heat at the rate of 880W to the surrounding air. The Reynold’s number at a distance of 0.5 m from the plate is 10 6 and the Prandtl number at mean film temperature is 0.7. The thermal conductivity of air is 0.02 W/mK. Assume the local Nusselt number at a distance L from the leading edge of the plate to follow the relation
The value of A is ________ × 10–3. 422. A reciprocating compressor has bore equal to stroke and it run at a speed of 600 rpm. Inlet air has temperature and pressure of 25°C and 100 kPa. The free air conditions are 105 kPa, 15°C and 8.564 m3/min. The volumetric efficiency of the compressor is 88 percent. The crank radius is ______ cm.
423. A low carbon steel plates is to be welded by the manual metal arc welding process using a linear V-I characteristics DC power source. The following data are available
The heat input into work piece will be ______________W. 424. Atmospheric air at a flow rate of 3 kg/s (on dry basis) enters a cooling and dehumidifying coil with an enthalpy of 85 kJ/kg of dry air and a humidity ratio of 19 grams/kg of dry air. The air leaves the coil with an enthalpy of 43 kJ/kg of dry air and a humidity ratio of 8 grams/kg of dry air. If the condensate water leaves the coil with an enthalpy of 67 kJ/kg, the required cooling capacity of the coil is _______kW. 425. The past records at an emergency room of a hospital in a rural area indicate an average of 10 arrivals per day. The demand for emergency room service is distributed according to Poisson distribution. The probability of less than 3 arrivals is __________ percent. 426. An item is produced at the rate of 50 items per day. The demand occurs at the rate of 25 items per day. If the setup cost is Rs. 100 per setup and holding cost is Rs. 0.01 per unit of item per day, the minimum total cost per run is Rs. __________. 427. An air standard Otto cycle develops maximum work and operates between 300 K and 1200 K as minimum and maximum temperatures respectively. The air standard efficiency of cycle is ______%. 428.
Maximum slope of the curve y = –x3 + 3x2 + 9x – 27 is _____.
429. The value of closed integral around the hypocycloid x2/3 + y2/3 = a2/3 is _____. The main process which takes place in a desert-cooler is
adiabatic saturation
430. There are two columns, made of same material. Column 1 has minimum buckling load of 100 N and slenderness ratio is 2. Column 2 has buckling load of 200 N. What will be the slenderness ratio of column 2? The term fully-developed laminar flow means that the velocity profile does not change in the direction of flow
Which of the following cycle working with in same temperature limits has the highest work ratio? Rankine cycle
431. Heat is generated in a long 0.3 cm diameter cylindrical electric heater at a rate of 180 3 W/cm . The heat flux at the surface of heater in steady operation is ____________ W/cm2 . 432. An open U-tube containing water, mercury of specific gravity 13.6 is poured into one of its limbs so that length of column of mercury is about 20 mm. The level of water column in that limb is lowered by ____________ cm. 433. In a pert activity, the pessimistic, optimistic and most likely time to complete the activity are 8 days, 4 days and 6 days respectively. The probablistic time to complete the activity will be __________days 434. In a production or built up model of inventory control, production rate is 400 pieces per day and demand rate is 300 pieces per day and ordering cost and holding cost are 200 Rs. and 0.81 Rs. per day. The production factor for the given condition is ___________. 435. A parting tool has the back rake angle of 8°. The tool by mistake, was set 1.6 mm above the line of centres while machining a job of 40 mm outside diameter. The effective rake angle of the tool is __________ degree. 436. The diameter and rotational speed of a job are 80 mm and 480 rpm respectively. If chatter frequency is 120 Hz, then the chatter mark are found at a spacing of __________ (degree) on the job surface. 437. A stepper motor working on a CNC machine has 120 steps. The output shaft of the motor is directly coupled to a lead screw of pitch 10 mm, which drives a table. If the speed of table is 60 mm/s. then the frequency of pulse supply to the motor is ____________ Hz. 438. The probability that A speaks truth is 4/5, while this probability for B is 3/5. The probability that they contradict each other when asked to speak on a fact is ___________. 439.
The value of integral
The value of k is _____.
Consider the following 1. Thrust force will increase with increase in side cutting 2. Feed force will decrease with increase in side cutting 3. Radial force will increase with increase in side cutting edge angle. 1, 2 and 3
statements: edge angle. edge angle.
Consider the following statements: 1. A U-tube differential manometer is used upright if the pressure difference is small. 2. A U-tube differential manometer cannot be inclined at any angle. 3. A U-tube differential manometer is used inverted if the pressure difference is small. 4. A U-tube manometer cannot measure the vacuum pressure. only 3 is correct
440. A single row deep groove ball bearing is subjected to radial load of 1500 N and axial load of 1000 N. It has basic static load capacity = 7200 N and basic dynamic load capacity = 12000 N. [Take, Radial factor, X = 0.56, Thrust factor, Y = 1.2 Rotation factor V = 1] Rated life of the bearing is (in revolutions): 441. A structural member is designed by using total strain energy theory having maximum shear strength (sys) is 100 MPa. Poission ratio is 0.3. For the respective theory shape of safe boundaries is given below. What will be the length of major axis of the ellipse in MPa?
442.
For the following loading condition
Determine value of σx and τxy in MPa? 443. Two gear wheels, each with 25 teeth of involute form and pressure angle of 20° are required to give an arc of contact equal to 1.6 times the circular pitch. Find the addendum required in terms of the circular pitch. 444. A single cylinder, four stroke IC engine rotating at 1000 rpm has crank length of 50 mm and a connecting rod length of 120 mm. If the effective mass of reciprocating parts of engine is 1 kg. What is the approximate magnitude of the maximum shaking force created by the engine? 445. A disc clutch with a single friction surface has coefficient of friction equal to 0.25. The maximum pressure which can be imposed on the friction material is 2 MPa. The outer diameter of the clutch plate is 250 mm and its internal diameter is 126 mm. Assign uniform wear theory for the clutch plate, the maximum torque (in Nm) that can be transmitted is:
446. A refrigerator unit having a mass of 35 kg is to be supported on 3 springs, each having a spring stiffness S. The unit operates at 480 rpm. What will be the value of stiffness ‘S’ if only 10% of shaking force is allowed to be transmitted to the supporting structure ?
What will be the shape of elastic curve at section BC ? PARABOLIC 447. A straight bar of alloy [1 m × 12.5 mm × 4.8 mm] section is mounted on a strut testing machine and loaded axially until it buckles. Estimate the maximum central deflection (in mm) before material attains its yield point of 280 N/mm 2. (E = 72000 MPa. Neglect axial stress) 448. In a parallel flow heat exchanger, the inlet and outlet temperature of the hot fluid are 150°C and 90°C while that of the cold fluid are 30°C and 70°C respectively. For the same overall heat transfer coefficient and heat transfer, the % decrease in the surface area of the heat exchanger if counter flow arrangement is used is ___________ %. 449. For the system shown in Fig., if p1 = 60 kPa and V1 = 20 m/s, the downstream pressure p2 is _____________ kPa.
Neglect losses. Assume pressure immediately after the pipe expansion is p1. 450. The discharge through a reaction radial flow turbine is reduced by 25% when thickness of blade is taken into consideration as 15 mm. If diameter of the runner at inlet is 750 mm, then the number of blades on runner are ____________. 451. Solar radiations is incident on an opaque surface at a rate of 400 W/m 2. The emissivity of the surface is 0.65 and absorptivity to solar radiation is 0.85. The convection coefficient between the surface and the environment at 25°C is 6 W/m 2K. If the surface is exposed to atmosphere with an effective sky temperature of 250 K. The equilibrium temp. of the surface is ____________K.
452. The given figure shows an open cycle gas turbine employing reheat on T-S diagram. Assuming that the specific heats are same for both air and gas and neglecting the increase in mass flow rate due to addition of fuel, the efficiecy is ____________%.
453. For a gas power plant cycle temperature limits are 300 K and 1200 K respectively. The compression ratio of the plant cycle corresponding to maximum work output will be ____________. Take γ = 1.4 454. A resistance-capacitance relaxation circuit is used in an electrical discharge machining process. The capacitance in the circuit is 8 μF and the discharge voltage is 150 V. The spark cycle time, at which the average input required is 1.2 kW, is _______________ μ sec. 455. A simple refrigeration cycle uses R–134a as the working fluid. The temperture of the refrigerant in the evaporator is –10°C. The condensing temperature is 40°C. The cooling load is 150 W and the volumetric efficiency of the compressor is 80%. The speed of compressor is 720 rpm. The displacement volume of the compressor is ____________ × 10–4 m3/s. Properties of R–134a.
456. In a certain machining operation with a cutting speed of 50 m/min, tool life of 45 minutes was observed, when the cutting speed was increased to 100 m/min then tool life decreased to 10 minutes. If the tool change time is 3 minutes, then the cutting speed for maximum productivity is ____________ m/min. 457. A single cylinder, 4-stroke engine is fitted with a rope brake dynamometer. The diameter of the brake wheel is 600 mm and the rope diameter is 25 mm. The dead weight on the brake is 200 N and the spring balance reads 30 N. If the engine runs at 450 rpm, the brake power of the engine is ______________ kW.
Consider the following statements: 1In grey cast iron, graphite exists in the form of flake. 2. When molten iron is cooled slowly with Mg, it becomes grey cast iron. 3. Ductile iron is formed when molten cast iron is cooled with Mg. 1 and 3 Consider the following statements pertaining to a vapour compression type refrigerator: 1. The condenser rejects heat to the surroundings from the refrigerant. 2. The evaporator absorbs heat from the surroundings to be cooled. 3. Both the condenser and evaporator are heat exchanger with refrigerant as a common medium. 4. The amount of heat exchanged in condenser and evaporator are equal under steady conditions. Which of the above statements are correct?
1, 2 and 3
458. The bar given below is rotating at an angular velocity (ω 0) = 10 rad/sec along vertical centroidal axis and having angular retardation (α) of –1 rad/s 2. Find the maximum stress developed (kN/m2) on the bar at t = 3 s. (Neglect shear stress induced.)
459. For a given Whitworth quick return mechanism, length of crank and length of driving crank are 30 cm and 75 cm respectively. What will be the quick return ratio for the given construction? Which of the following does not hold true for bending stress and shear stress? At extreme fibers bending stress in maximum and shear stress is zero. Bending stress acts perpendicular to cross section and shear stress acts parallel to crosssection.
At neutral axis both bending stress and shear stress are zero.
Shape of bending stress distribution is independent of shape of cross-section but shear stress distribution depends on cross-section. In a hydrodynamic bearing, there is:
boundary lubrication when the speed is very low or when the load is excessive
no lubricant between the journal and the bearing a forced lubricant between the journal and the bearing All of the above Measurement of velocity without any obstruction to the flow in a pipe may be made by
laser-doppler anemometer
hot-wire anemometer hot-film anemometer pitot-static probe In a two stage gas turbine plant operating on a Brayton cycle with regeneration Work output increases but cycle efficiency decreases Work output decreases has but cycle efficiency remains unchanged
Cycle efficiency increases but work output remain unchanged
Both cycle efficiency and work output increases. 460. Heat is generated in a 10 cm diameter spherical radioactive material whose thermal conductivity is 25 W/mK uniformly at a rate of 15 W/cm 3. If the surface temperature of the material is measured to be 120°C. The center temperature of the material during steady operation is ____________°C. 461. The velocity of an airplane is measured with a pitot tube. If the pitot tube measures 800 mm of water, the speed of the airplane is ____________ m/s. Take ρair = 1.23 kg/m3, g = 9.81 m/s2. 462. For a particular product in a company, the fixed cost is Rs. 10 and sales volume and profits are Rs. 500 and Rs. 90 respectively. Now the owner of the company wants to increase its profit by Rs. 60, then the needs of increase in sales volume Rs. ____________ . 463.
The probability distribution for the sale of a product is as follows:
On the sale of an item the profit is Rs. 500. The expected profit is Rs. __________. 464.
Ratio of lattice parameter (a) to atomic radius (r) for Gold is ____________.
465. In the orthogonal cutting, the depth of cut is 0.6 mm at a cutting speed of 3 m/s. If the cutting speed is 8 m/s, then the depth of cut is ___________ mm. (Assume no side flow) 466. An aluminium billet of 220 mm diameter is extruded with an extrusion ratio 8. If the effective flow stress in compression is 280 MPa. Then the ideal extrusion pressure (in MPa) is ___________.
467. Given the matrix ___________.
468.
The value of integral
The sum of eigen values of 4A–1 + 3A + 2I is
is __________ .
469. A sample of steam from a boiler drum at 3 MPa is put through a throttling calorimeter in which the pressure and temperature are found to be 0.1 MPa, 120°C. The quality of the sample taken from the boiler is The properties of saturated steam at 3 MPa: hf = 1008.42 kJ/kg and hg = 2804.12 kJ/kg Superheated steam at 0.1 MPa and 120°C: h = 2716.28 kJ/kg During ultrasonic machining, the metal removal rate is affected by the
Hammering action of abrasive particles
Rubbing action between tool and workpiece Low frequency of sound waves High frequency of eddy currents 470. A tube of mean diameter 5 cm and thickness 2 mm is made of mild steel with an elastic limit of 250 N/mm2 under simple tension. Calculate the torque (N-m) which may be transmitted by the tube with a factor of safety of 2.5 using maximum shear stress theory. 471. A structural member is designed by using von Mises theory, having maximum shear strength (Sys) is 100 MPa. Poisson ratio is 0.3. Find the length of semi-major axis (MPa) of ellipse given below.
472. The mechanism shown in figure is driven by turning A0A. Find out geometrically the maximum transmission angle.
473. In a spring controlled governor, the controlling force curve is a straight line. The balls are 400 mm apart when the controlling force is 1500 N and 240 mm when it is 800 N. The mass of each ball is 10 kg. What will be the speed at which the governor runs when the balls are 300 mm apart? 474. A pair of spur gears with 20°-full depth involute teeth consists of 20 teeth pinion meshing with a 41 teeth gear. The module is 3 mm while the face width is 40 mm. The material for pinion as well as gear is steel with an ultimate tensile strength of 500 N/mm 2. The gears are heat treated to a surface hardness of 350 BHN. What is the wear strength of the gear design? 475. The successive amplitudes of vibrations of vibratory system as obtained under free vibration are 0.69, 0.32, 0.19, 0.099 units respectively. Determine the damping ratio of the system. 476.
For the given loading condition, find the load P?
477. A composite bar is subjected to pure torsion as shown in figure. The torsional stiffness (K) of two bars are 100 and 200 N. Find the torque induced in both the bars (in Nm)
478. Air flows through the supersonic adiabatic nozzle as shown in fig. The inlet conditions are 7 kPa and 420°C. The nozzle exit diameter is adjusted such that the exiting velocity is 700 m/s. The exit diameter of the nozzle is
479. Air (cp = 1000 J/kgK) enters a 160 mm diameter and 19 m long underwater duct at 50°C and 1 atm at an average velocity of 7 m/s and is cooled by the water outside. If the average heat transfer coefficient is 35 W/m 2K and the tube temperature is nearly equal to water temperature of 5°C, the exit temperature of air is ____________°C. 480. A reaction turbine, whose runner radii are ro = 300 mm and ri = 150 mm, operates under the following conditions:
Assuming hydraulic efficiency is 100%, the head on the turbine is ____________ m. (Take g = 9.81 m/s2) 481. In a flat plate, water with velocity 5 m/s and heat transfer coefficient of 1000 W/m 2K. The Stanton number for the given flow will be ____________.
482. The isentropic heat drop in the nozzle of an impulse steam turbine with a nozzle efficiency 0.8, blade velocity ratio 0.4 and mean blade velocity 150 m/s in kJ/kg is ____________. 483. For a increase in specific heats ratio of 10% in Brayton cycles the change in cycle efficiency will be ____________%. Take pressure ratio 4, and initial specific heats ratio is 1.4. 484. A bar of 60 mm diameter is being cut orthogonally and is reduced to 54 mm by a cutting tool. In a case, mean length of the chip is 57 mm. If the rake angle is 6°, shear angle will be ___________ degree. 485. The data of heat load in a small restaurant is Heat flow through walls, roof and floor = 22000 Solar heat gain through glass = 7000 Equipment sensible heat gain = 10500 Equipment latent heat gain = 2500 The sensible heat factor of restaurant is ____________.
given: kJ/hr. kJ/hr kJ/hr kJ/hr
486. For a production and built-up model, the production rate and demand rate are 200 unit per day and 100 unit/day, ordering/set up cost are Rs. 200 per batch and holding cost of inventory is Rs. .81 per day. Now if the production rate becomes infinite, the variation in economic lot quantity is __________ units. 487. During a steady state gas metal are welding with direct current electrode positive, the welding current, voltage and welding speed are 150A, 30V, 6 m/min. A metallic wire electrode of diameter 1.2 mm is being fed at a constant rate of 12 m/min. The density, specific heat and melting temperature of the wire electrode are 7000 kg/m 3, 500 J/kg, 1530 °C.Assuming ambient to be 30°C and neglect latent heat of melting, further consider that of the total electrical power is available for melting. The melting efficiency of the wire electrode (%) is _______________. 488. A large four-stroke cycle diesel engine runs at 2000 rpm. The engine has a displacement of 25 litres and a brake mean effective pressure of 0.6 MN/m 2. It consumes 0.018 kg/s of fuel (calorific value = 42000 kJ/kg). The thermal efficiency is ____________ %.
489.
The value of integral
(Where R is the quadrant of the circle x2 + y2 = 4 with x ≥ 0, y ≥ 0) An inverted U-tube manometer is more sensitive than an upright manometer because the manometric liquid is lighter than the working liquids. The entropy of fixed amount of an ideal gas decreases in every isothermal compression Edge dislocation is a one dimensional defect Which one of the following is correct? In a sensible cooling or heating process The humidity ratio remains constant.
490. A circular disc rolls down without slip on an incline plane. The ratio of its rotational kinetic energy to the total energy is 491. The sleeve and each rotating mass of a porter governor weigh respectively 200 N and 50 N. If the friction at the sleeve is 10 N, then coefficient of detention would be
492. Module and length of line of action of set of spur gear are 4 mm and 18 mm respectively. If pressure angle is 20° then what will be the contact ratio of the gear ?
Select the correct statement:
where Cd,V, Cd,N and Cd,O are the coefficients of discharge for venturimeter, nozzle and orificemeter respectively.
a
493. Consider an actual regenerative Rankine cycle with one open feed water heater. For each kg of steam entering the turbine, m kg steam with specific enthalpy of h1 is bled from the turbine. Specific enthalpy of water entering the heater is h2 . The specific enthalpy of saturated liquid leaving the heater is equal to 494. The particular integral of the differential equation is given by 495. Hot water flows through a PVC (K = 0.092 W/mk) pipe whose inner diameter is 2 cm and outer diameter is 2.5 cm. The temperature of the interior surface of this pipe is 50°C and the temperature of exterior surface is 20°C. The rate of heat transfer per unit of pipe length is ___________ W/m. 496. A 20 cm diameter pipe 30 km long transports oil from a tanker to the shore at 0.01 3 m /s. The power required to maintain the flow is __________ kW. Take μ = 0.1 Ns/m2 , ρ = 900 kg/m3 for the oil. 497. In a production system, the damage, handling, inspection, insurance, transportation and interest cost are Rs.10, Rs. 50, Rs. 15, Rs. 20, Rs. 40 and Rs. 30 respectively. The total holding cost will be (in Rs.)__________. 498. A sine bar has a length of 180 mm, each roller has a diameter of 12 mm during taper angle measurement of a component. The height from the surface plate to the centre of a roller is 80 mm. The calculated taper angle (in degree) is ___________.
499. It is required to reduce the 15 mm diameter of steel to 10 mm with a die. The semi die angle is 7° and the coefficient of friction is 0.05. Mean flow stress is given as 600 MPa, then the drawing stress would be ____________ MPa. 500. A steel rod 10 m long is at a temperature of 20°C. The rod is heated to a temperature of 60°C. The stress induced in the rod if it is allowed to expand by 4 mm, is _______ MPa. (E = 200 GPa, α = 12 × 10–6 per °C) 501. Consider an expression f (z) = poles is __________
The sum of residues of the function at its
502. A certain gas has cp = 0.914 kJ/kgK and cv = 0.653 kJ/kgK. The molecular weight of the gas is Which of the following is not correct for core design in casting? Dry strength of core should be enough to resist metal pressure Core sand should have high refractoriness
Core sand should be of lower strength than the moulding sand
Core sand should be of high permeability Consider the following statements: 1. The diverging part of a venturimeter is shorter than the converging part. 2. The eddies formation in a flow nozzle is just downstream of the nozzle. 3. Movement of the float in rotameter enables its stability in vertical position. 4. The trajectory of a jet issuing from a nozzle is parabolic. Of these statements: 2, 3 and 4 are true 503. A bracket attached to a column by means of 4 identical rivets is subjected to an eccentric force of 10 kN as shown below. If permissible shear stress is 60 MPa then, the diameter of rivets will be:
504. A structural member during its functioning is subjected to maximum and minimum principle stress of 200 MPa and – 100 MPa E = 300 GPa μ = 0.3 2 Find the volumetric strain energy per unit volume stored in the member in kN/m .
505. Assume a cylindrical shell with hemispherical ends having thickness ‘t1 ’ for cylindrical part and thickness ‘t2 ’ for hemispherical ends. Assume internal diameters same for both. Determine the value of (t1/t2) for no distortion of the juncture under pressure. Take μ = 0.25. 506. Two standard full depth gears of pressure angle 14.5° have a module of 5 mm. The pinion has 15 teeth while the gear has 60 teeth. If the addendum of the gear is equal to the module.To what value should be the pressure angle be increased in order to eliminate the interference? 507. A cylinder of diameter 10 mm and mass 2 kg floats vertically in a liquid of mass density 900 kg/m3 as shown in figure. It is depressed slightly and released. The period of its oscillation will be, if specific gravity is 1.2.
508. The load on the journal bearing is 180 kN due to turbine shaft of 400 mm diameter running at 1500 rpm. If the bearing temperature is 60°C and viscosity of the oil at 60°C is 0.02 kg/m-s and the bearing clearance is 0.25 mm then the amount of heat to be removed by the bearing is: [Allowable bearing pressure = 1.6 MPa] 509. A machine is coupled to a power source. The machine requires constant torque but torque supplied by the power source is (1000 + 300 sin θ) N-m. Mass moment of inertia of the flywheel is 200 kg-m2. What is the maximum angular acceleration of the flywheel and at what position does it occur? 510. Find deflection at point D:
511. A horizontal beam 10 m long simply supported at its end carries a load which varies uniformly from 10 N/m at one end to 50 N/m at the other end. Find the distance from the left at which bending moment would be maximum 512. Assuming air as an ideal gas, the heat transfer from the system is 513. The area bounded by the parabola y = x2 and the line y = 2x + 3 in first quadrant is 514. The engine oil at 150°C is cooled at 80°C in a parallel flow heat exchanger by water entering at 25°C and leaving at 60°C. The heat exchanger effectiveness will be ___________. 515. The venturimeter shown reduces the pipe diameter from 10 cm to a minimum of 5 cm. Assuming ideal conditions, the mass flow rate is __________ kg/s.
516. High-speed air jets strike the blades of a turbine rotor tangentially while the 1.5 m diameter rotor rotates at 140 rad/s as shown in Fig. There are 10 such 4 cm diameter jets. The maximum power output is ________ kW. Take density of air is 2.4 kg/m3 .
517. A 12 mm diameter mild steel sphere (K = 4.25 W/mk) is exposed to cooling airflow at 27°C resulting in the convective coefficient h = 114 w/m2 k. The time required to cool the sphere from 540°C to 95°C is ___________ sec. Use ρ = 7850 kg/m3; α = 0.043 m2/hr 518. For a reciprocating compressor, swept volume is 1000 ml and compression ratio is 6 and pressure ratio is 4. The volumetric efficiency or the compressor will be ___________%. Assume polytropic index 1.3 519.
For the given diagram of Brayton cycle
Assume specific heat of air and gas are equal. The efficiency of the cycle will be ___________. 520. A drilling machine is provided with minimum spindle speed 35 rpm and maximum spindle speed of 300 rpm. If number of speed is 6, then the 3 rd spindle speeds that are likely to be available on the machine will be _____________ rpm.
521. Moist air is heated by steam condensing inside the tubes of heating coil as shown in Fig. Part of the air passes through the coil and part is by-passed around the coil. The air which by-pass the coil is _________ kg/min.
522. In a manufacturing plant of Honda Activa, the various work stations and their total task time are given below:
The ratio of balance delay (%) and line efficiency (%) is ___________.. 523. In a work measurement trial process 100 observations were made, and in this preliminary study 25 observations showed be machines to be idle. The no. of random observations required for 95% of confidence level and +5% accuracy are _________. Take (Z = 2 for 95% accuracy level) Z = standard normal variate 524. An orthogonal cutting operation is being carried out and has the following condition, t = 0.18 mm, tc = 0.32 mm, width of cut = 5 mm, cutting speed, v = 2.5 m/s, rake angle, α = 10°, cutting force, Fc = 500 N and thrust force, Ft = 150 N. The percentage of total energy that is dissipated in the shear plane would be _________. 525. A spark ignition engine has a compression ratio of 8 and the specific volume before compression is 0.9 m3/kg. Net heat interaction per cycle is 1575 kJ/kg. The mean effective pressure (in bar) is __________. 526. A numerical solution of the equation can be obtained using NewtonRaphson method. If the starting value is x = 2 for the iteration, then the value of x after two successive iterations is equal to __________.
527. In estimating the number of bricks in a pile, which is measured to be (5 m × 10 m × 5 m), count of bricks is taken as 100 bricks per m 3. If the tape is stretched 2% beyond its standard length, then the error in total cost will be Rs. __________. [The cost of bricks in Rs. 2000 per thousand bricks]. In a real gas equation pv = zRT, depending on the values of pressure and temperature of the real gas, the value of z may be less than one, may be greater than one or equal to one 528. If the maximum and minimum resultant forces of the two force acting on a particle are 40 kN and 10 kN respectively, then the two forces would be Match List-I (Chemical formula of refrigerant) with List-II (Numerical designation) and select the correct answer using the codes given below the lists: List-I A. NH3 B. CCl2F2 C. CHClF2 D. C2F3Cl3
List-II 1. 12 2. 22 3. 40 4. 113 5. 717
5124 Consider the following statement about theory of failure are correct.
1. Mohr’s theory is used for brittle materials. 2. Graphical representation of maximum shear stress theory is of hexagonal type. 3. In pure shear condition, maximum shear stress theory is uneconomical. 4. Maximum principle stress theory is used for brittle material. 1, 2, 3 and 4
