Q.1.
A body under the action of a force F=6 i - 8j + 10k.acquires an acceleration of 1 m/s2 The mass of this body must be [ CBSE-PMT 2009]
-
11%
a) 10kg
-
21%
b) 20 kg
-
63%
c) 10√2kg
-
5%
d)2√10kg
Q.2.
A light string passing over a smooth light pulley connects two blocks of masses m1 and m2 ( vertically) if the acceleration of system is g/8, then the ratio of masses is ... [ CBSE-PMT 2010]
-
28%
a)8:1
-
39%
b) 9:7
-
22%
c)4:3
-
11%
d)5:3
Explanation
Q.3.
A 60kg man stands on a spring scale in the lift. At same instant he finds, scale reading has changed from 60 kg to 50kg for a while and comes back to the original mark. What should we conclude? [ AFMC 2007]
-
31%
a) The lift was in constant motion upwards
-
31%
b) The lift was in constant motion downwards
-
25%
c)The lift while in constant motion upwards is stopped suddenly
-
12%
d)The lift while in constant motion downwards, is suddenly stopped
Q.4.
In Newton's second law F =m a , a is the acceleration of the mass 'm' with respect to [ AFMC 2011]
-
0%
a) Any observer
-
44%
b) Any inertial observer
-
17%
c)an observer at rest only
-
39%
d)an observer moving with uniform speed only
Q.5.
A motor cycle is going on an over bridge of radius R. The driver maintains a constant speed. As the motor cycle is ascending on the over bridge the normal force on it... [ AFMC 2006]
-
62%
a) increases
-
12%
b) decreases
-
25%
c) remains the same
-
0%
d) fluctuates erratically
Explanation
Q.6.
The limiting friction is ... [ AFMC 2007]
-
56%
a)always greater than the dynamic friction
-
17%
b) always less than the dynamic friction
-
6%
c)equal to the dynamic friction
-
22%
d)sometimes greater and sometimes less than the dynamic friction
Q.7.
A person swimming in a fresh water pool obeys [ AFMC 2003]
-
17%
a) Newton's second law
-
11%
b) Gravitational law
-
50%
c)Newton's third law
-
22%
d)Newton's first law
Q.8.
When a car moves on a road with uniform speed of 30km/hr, then the resultant force on the car is ... [ AFMC 2004]
-
35%
a) The driving force, drives the car in the direction of propagation of car
-
24%
b) The resistive force acts opposite to the direction of propagating of car
-
41%
c)zero
-
0%
d)none of these
Q.9.
A cyclist moving with a speed of 4.9 m/s on a level road can take a sharp circular turn of radius 4m, then coefficient of friction between the cycle tyres and road is ... [ AFMC 2002]
-
7%
a) 0.71
-
73%
b) 0.61
-
7%
c) 0.31
-
13%
d) 0.81
Q.10.
A spring of length L of uniform cross-section is spread on a smooth plane. One of its end is pulled by a force F as shown in the figure. The Tension in the spring at a distance 'l' from this end is .. [ AFMC 2010]
-
13%
a)
-
53%
b)
-
27%
c)
-
7%
d)
Explanation
Q.11.
A bullet of mass m is fired from a gun of mass M. The recoiling gun compresses a spring of force constant k by a distance d. Then the velocity of bullet is .. [ AFMC..2011]
-
29%
a)
-
21%
b)
-
29%
c)
-
21%
d)
Explanation
Q.12.
Which of the following is self adjusting force? [ AFMC 2009]
-
13%
a) kinetic friction
-
47%
b) static friction
-
20%
c) Nuclear force
-
20%
d) None of these
Q.13.
A body of mass 4.975kg is lying on the frictionless floor. A mass of 25gm moving with 400m/s strikes the mass and gets embedded in it. The velocity of the body combined after collision is ... [ AFMC 2006]
-
58%
a) 2 m/s
-
17%
b) 4 m/s
-
17%
c) 1 m/s
-
8%
d) none of these..
Explanation
Q.14.
The rocket engine lift a rocket from the earth, because hot gases: [ AIIMS 1998]
-
13%
a)push it against the air with very high velocity
-
27%
b) push it against the earth with very high velocity
-
27%
c)heat up the air which lifts the rocket with very high velocity
-
33%
d)react against rocket and push it up with very high velocity
Q.15.
A man of mass 60kg records his weight on a weighing machine placed inside a lift. the ratio of weight of man recorded when lift ascending up with uniform speed of 2m/s to when it is descending down with uniform speed of 4m/s [ AIIMS 2007}
-
0%
a) 0.5
-
46%
b) 1.0
-
46%
c)2.0
-
8%
d)none of these
Q.16.
When a horse pulls a wagon, the force that causes the horse to move forward in the force [ AIIMS 2010]
-
31%
a) the ground exerts on it
-
15%
b) it exerts on the ground
-
46%
c)the wagon exerts on it
-
8%
d)it exerts on the wagon
Q.17.
A person standing in an elevator. in which situation he finds his weight less? [ AIIMS 2005]
-
17%
a) When the elevator moves upward with constant acceleration.
-
42%
b) When the elevator moves downward with constant acceleration
-
17%
c) When the elevator moves upward with uniform velocity
-
25%
d) When the elevator moves downward with uniform velocity
Q.18.
A 1kg particle strikes a wall with a velocity 1m/s at an angle 30° and reflects at the same wall in 0.1 second then the force will be: [ AIIMS 1999]
-
25%
a)30√3 N
-
25%
b) 0
-
8%
c)40√3 N
-
42%
d)10√3 N
Explanation
Q.19.
A 150 g tennis ball coming at a speed of 40 m/s is hit straight back by a bat to a speed of 60 m/s. the magnitude of the average force F on the ball, when it is in contact for 5 ms is ... [ AIIMS 2011]
-
8%
a) 2500 N
-
33%
b) 3000 N
-
33%
c)3500 N
-
25%
d)4000 N
Explanation
Q.20.
A gardener holds a hosepipe through which water is gushing out at a rate of 4 kg/s with speed 2m/s. The moment the speed of water is increased to 3m/s, the gardener will experience a jerk of ... [ AIIMS 2011]
-
36%
a)4 N in backward direction
-
27%
b)8 N in forward direction
-
36%
c)8 N in backward direction
-
0%
d)4 N in forward direction
Q.21.
A bomb of mass 3.0 kg explodes in air into two pieces of masses 2.0kg and 1.0kg. the smallest mass goes at a speed of 80 m/s. the total energy imparted to the two fragments is.. [ AIIMS 2004]
-
11%
a) 1.07 kJ
-
11%
b) 2.14 kJ
-
44%
c) 2.4 kJ
-
33%
d) 4.8 kJ
Q.22.
If the force on rocket, moving with a velocity 500 m/s is 400N, then the rate of combustion of the fuel will be.. [ AIIMS 1997]
-
40%
a)0.8 kg/sec
-
0%
b) 10.8 kg/sec
-
60%
c)8 kg/sec
-
0%
d)1.6 kg/sec
Explanation
Q.23.
The velocity of bullet is reduced from 200m/s to 100 m/s while traveling through a wooden block of thickness 10cm. Assuming it is to be uniform, the retardation will be.. [ AIIMS 2001]
-
25%
a) 15×104 m/ s2
-
38%
b) 10×104 m/ s2
-
0%
c)12×104 m/ s2
-
38%
d)14.5 m/ s2
Q.24.
An 80 kg person is parachuting and is experiencing a downward acceleration of 2.8 m/s2 . The mass of the parachute is 5kg. The upward force on the open parachute is .. ( g=9.8 m/s2)
-
33%
a)595 N
-
11%
b) 675 N
-
44%
c)456 N
-
11%
d)925 N
Q.25.
A parachutist after bailing outfalls 50 m without friction. When parachute opens. If decelerates at 2m/sHe reaches the ground with a speed of 3m/s. At what height, did he bail out? take g=9.8 m/s2 [ AIIMS 2009]
-
0%
a) 182 m
-
12%
b) 91 m
-
50%
c) 111 m
-
38%
d) 293 m
Q.26.
A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively.. [ AIEEE2002]
-
12%
a)g, g
-
12%
b) g-a, g-a
-
62%
c)g-a, g
-
12%
d)a, g
Q.27.
A spring balance is attached to the ceiling of lift. A man hangs his bag on the spring and the spring reads 49N, when the lift is stationary. If the lift moves downwards with an acceleration of 5 m/s2, the reading of the spring balance will be [ AIEEE-2003]
-
57%
a) 24N
-
0%
b) 74N
-
29%
c)15N
-
14%
d)49N
Q.28.
A light string passes over a smooth light pulley connects two blocks of masses m1 and m2 ( vertically). If the acceleration of the system is g/8, then the ratio of the masses is [ AIEEE 2002]
-
11%
a) 8:1
-
33%
b) 9:7
-
33%
c)4:3
-
22%
d)5:3
Explanation
Q.29.
One end of a mass less rope, which passes over a mass less and frictionless pulley P is tied to a hook C while the other end is free. Maximum tension that the rope can bear is 840N. With what value of maximum safe acceleration (in m/s2) can a man of 60 kg climb on the rope [ AIEEE 2002]
-
43%
a) 16
-
29%
b) 6
-
14%
c) 4
-
14%
d) 8
Q.30.
Three identical blocks of mass m=2 kg are drawn by a force F=10.2N on a friction less surface, then what is the tension (in N) in the sting between the blocks B and C? [ AIEEE 2002]
-
10%
a)9.2
-
20%
b) 3.4
-
0%
c)4
-
70%
d)9.8