ANDHERI / BORIVALI / DADAR / CHEMBUR / THANE / MULUND/ NERUL / POWAI
IIT-JEE 2014
TW TEST
TIME: 1 ½ HRS
MARKS: 65
TOPICS: LAWS O MOTION
DATE:
3 N 2
1
1. Two blo block ckss of of mas masse sess 2 kg kg and and 1 kg kg are are in in con conta tact ct with with each each othe otherr on on a frictionless table. When a horizontal force of 3.0 N is applied to the block of mass 2 kg, the vale of the force of contact between two blocks is! "a# $ N "b# 3 N "c# 2 N "d# 1 N 2.
%n the the fig figre re give given n bel below ow,, wha whatt is the the read readin ing g of of the the bala balanc nce& e&
kg −1 "Take g ' 10 N "a# 10 N 3.
# "b# 20 N
"c# ( N
"d# zero
Three hree blo blocks cks of of mas masse sess 2 kg, kg, 3 kg kg and and ( kg kg are are co connec nnecte ted d to to each other with light string and are then placed on a smooth frictionless srface. The s)stem is plled with a force * from the the side side of the the ligh lighte terr mass ass so that that is moves oves with with an
T2 s −2 T1 acceleration of 1 m . and denotes the tensions in the other strings. The vale of * is! "a# 2 N "b# 3 N "c# ( N "d# 10 N s $.
The The elev elevat ator or sho shown wn in in the the fig figre re is is desc descen endi ding ng,, with with an an acce accele lera rati tion on of of 2 m . The mass of the block + ' 0.( kg. The force eerted eer ted b) the block + on the block - is! 10m s
2
"Take g '
#
"a# 2 N (.
−2
"b# $ N
"c# N
"d# / N
Two mas masse sess of / kg kg and and $ kg kg are are conn connec ecte ted d b) a str strin ing g as sho shown wn in in the the figre over a frictionless plle). The acceleration of the s)stem is!
2 m s −2
$ m s −2 "a#
"b#
./ms −2 "c#zero
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"d#
:
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.
Two bodies of mass $ kg and kg are attached to the ends of a massless, inetensible string passing over a fied and smooth plle). The $ kg mass is attached to the table
T1 top b) another string. The tension in this string g = 10 m s
is eal to
2
"Take "a# 20 N
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# "b# 2( N
:
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"c# 10. N
"d# 10 N
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1 .
Three forces are acting on a particle of mass m initiall) in eilibrim. %f the first 2 forces "
( 3 )
2 # are perpendiclar to each other and sddenl) the third force acceleration of the particle is 3 1 + 2 1 − 2
m
m
"a# /.
is removed, then the
1
m
"b#
m
"c#
"d#
+ plmb bob is hng from the ceiling of a train compartment. The train moves on an inclined track
a =g 2
30 o
of inclination with horizontal. +cceleration of train p the plane is string spporting the bob makes with normal to the ceiling in eilibrim is
(
tan −1 2
30 o "a# .
and
3
)
tan −1
"b#
(
3 2
)
"c#
. The angle which the
tan −1 ( 2 ) "d#
+ssming that the block - alwa)s remains horizontal, hence the acceleration of - is
m s2
2 m s2
"a#
"b#
$ m s2 "c# 10.
"d# none of these
+s shown in the fig., if acceleration of 4 with respect to grond
( m s2 is
, then
( m s2 "a# +cceleration of m with respect to 4 is
( m s2 "b# +cceleration of m with respect to grond is
2 m s2 "c# +cceleration of m with respect 4 is
10m s 2 "d# +cceleration of m with respect to grond is 11.
+ painter of mass 4 stands on a platform of mass m and plls himself p b) two ropes which hang over plle) as shown in fig. 5e plls each rope with force * and moves pward with a niform acceleration a. *ind a neglecting the fact that no one cold do this for long time.
$* + ( 24 + m ) g
$* + ( 4 + m ) g
$* − ( 4 + m ) g
$* − ( 4 + m ) g
4 + 2m
4 + 2m
4+m
24 + m
"a#
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"b#
:
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"c#
"d#
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12.
Two trolle) + and - are moving with accelerations a and 2a respectivel) in the same direction. To an observer in trolle) +, the magnitde of psedo force acting on a block of mass m on the trolle) - is "a# zero "b# ma "c# 2 ma "d# none
13.
6)stem is shown in the figre and man is plling the rope from both sides with constant speed 78. Then the velocit) of the block will be
1$.
3
3
$
2
$
"a# "b# "c# "d# none 6)stem is shown in figre and wedge is moving towards left with speed 2 m9s. Then velocit) of the block - will be
3 "a# m9s "c# 2 m9s 1(.
"b# 1 m9s "d# $ m9s
%n the figre shown, the speed of the trck is v to the right. The speed with
θ = 0 o which the block is moving p at "a# v
1.
"b# 2v93
is! "c# 3v9$
"d# none
+ s)stem is shown in the figre. +ll speeds shown are with respect to grond. The speed of -lock + with respect to grond is ! "a# 20 m9s
"b# 2( m9s
"c# 1( m9s
"d# 10 m9s
1.
%n the figre if blocks + and - move with same horizontal acceleration de to eternal force applied on -, there is no friction between + and - , then the magnitde of interaction force between the two blocks will be ! "a# 2 mg 9 cos θ "b# 2 mg cos θ "c# mgcosθ "d# none of these
1/.
Two masses m1 and m2 which are connected with a light string are placed over a frictionless plle). This set p is placed over a weighing machine, as shown. Three combination of masses m 1 and m2 are sed, in first case m1 ' kg , and m 2 ' 2kg, in second case m 1 ' ( kg and m 2 ' 3 kg and in third case m1 ' $kg and m 2 ' $ kg. 4asses are held stationar) initiall) and then released. %f the readings of the weighing machine after the release in three cases are W1 , W2 and W3 respectivel) then! "a# W1:W2: W3 "b# W1; W2; W3 "c# W1 ' W2 ' W3 "d# W1 ' W2; W3
1.
-lock + of mass m is placed over a wedge - of same mass m. +ssming all srfaces to be smooth, the displacement of block + in 1 s if the s)stem is released from rest is
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:
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( 1 + sin θ ) g ( 1 − sin θ ) 2
gsin θ
2
2
"a#
"b# g
cos 2 θ
g
1 + sin 2 θ
"c#
sin 2 θ 1 + sin 2 θ
"d#
20.
*orce eerted b) the floor of a lift on the foot of a bo) standing on it is more than actal weight of the bo) if the lift is moving "a# down and speed is increasing "b# p and speed is increasing "c# p and speed is decreasing "d# down and speed is decreasing
21.
+ bod) of mass ( kg is
30 o
0o angles
sspended b) the strings making
and
with the
horizontal as shown in fig.
( g = 10 m s ) 2
T2 = 2(N
T1 = 2(N "a#
"b#
T2 = 2( 3N
T1 = 2( 3N "c#
"d#
22.
+ painter is appl)ing force himself to raise him and the bo with an acceleration of ( m9s2 b) a massless rope and plle) arrangement as shown in figre. 4ass of painter is 100 kg and that of bo is (0 kg. %f g '10 m9s 2 , then ! "a# Tension in the rope is 112( N "b# Tension in the rope is 22(0 N "c# *orce of contact between the painter and the floor is 3( N "d# The pll force of the painter on the rope is frictional force
23.
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:
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2$.
The plle) moves p with a velocit) of 10 m9sec. Two blocks are tied b) a string which passes over a plle). The velocit) = will be >>>>>>>>>>.
↓ ?iven! =- ' ( m9s
2(.
The three blocks shown move with constant velocities. *ind the velocit) of block + and -. ?iven =@2 = 10 m 9 s ↓, =A = 2 m 9 s ↑ .
ANDHERI / BORIVALI / DADAR / CHEMBUR / THANE / MULUND/ NERUL / POWAI
TOPICS: LAWS O MOTIONS +ANSWER KE,
1.d
2.a
3.d
$.b
(.c
.a
.a
/.b
.b
10.a
11.c
12.b
13.d
1$.c
1(.c
1.b
1.a
1/.b
1.d
20.b, d 21.a, d
0.(m 9 s ↑ 22.a, c, d
2(m 9 s ↑
23.
H!"# O$$%&!: A'#(!)%
2$.
:
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V A
= 10 m
s
↑,V = 22 m B
s
↓
2(.
MUMBAI / DELHI/ AKOLA / KOLKATA / LUCKNOW
