MCQ on Class 11 Physics Chapter 5 Laws of Motion

1 A gun of mass 1000 kg fires a projectile of mass 1 kg with a horizontal velocity of 100 m/s. The velocity of recoil of the gun in the horizontal direction is

A 5 m/s

B 0.1 m/s

C 15 m/s

D 20 m/s

View Answer

Answer:0.1 m/s

2 A block of wood is placed on a surface. A force is applied parallel to the surface to move the body. The frictional force developed acts

A normal to the surface upwards

B normal to the surface downwards

C along the direction of the applied force

D opposite to the direction of the applied force

View Answer

Answer:opposite to the direction of the applied force

3 A block of wood is placed on a surface. A force is applied parallel to the surface to move the body. The frictional force developed acts

A normal to the surface upwards

B normal to the surface downwards

C along the direction of the applied force

D opposite to the direction of the applied force

View Answer

Answer:opposite to the direction of the applied force

4 A body is sliding down a rough inclined plane which makes an angle of 30 degree with the horizontal. If the coeffcient of friction is 0.26, the acceleration in m/s² is

A 1.95

B 2.78

C 3.47

D 4.6

View Answer

Answer:2.78

5 A bullet of mass 25 g moving with a velocity of 200 cm/s is stopped within 5 cm of the target. The average resistance offered by the target is

A 1 N

B 2 N

C 3 N

D 4 N

View Answer

Answer:1 N

6 A body of mass 5 kg is travelling with a uniform velocity of 2 m/s. Its momentum is

A 10 kg m/s

B 7 kg m/s

C 2 .5 kg m/s

D 3 kg m/s

View Answer

Answer:10 kg m/s

7 The force required to produce an acceleration of 2 m/s² on a mass of 2 kg is

A 4 N

B 10 N

C 22 N

D 18 N

View Answer

Answer:4 N

8 The mass of a body which is equal to the ratio of the force acting on a body to the acceleration produced in the body is

A the gravitational mass

B the electromagnetic mass

C the internal mass

D the inertial mass

View Answer

Answer:the inertial mass

9 A machine gun fires a bullet of mass 40 g with a velocity of 1200 ms-1. The man holding it can exert a maximum force on 144 N on the gum. How many bullets can he fire per second at the most?

A one

B four

C two

D three

View Answer

Answer:three

10 A passenger in a moving bus is thrown forward when the bus is suddenly stopped. This is explained

A by Newtons first law

B by Newtons second law

C by Newtons third law

D by the principle of conservation of momentum

View Answer

Answer:by Newtons first law

11 A spherical ball of mass 10-6 kg hits a wall 1000 times per second normally with a velocity of 1000 m/s and rebounds with same velocity along the initial direction. The force experienced by the wall is

A 1 N

B 4 N

C 2 N

D 8 N

View Answer

Answer:2 N

12 A passenger sitting in a bus moving at uniform speed, feels pushed backward whenever the bus is accelerated forward. This type of force is called

A Gravitational force

B real force

C fictitious force or pseudo force

D frictional force

View Answer

Answer:fictitious force or pseudo force

13 Inside the nucleus, two protons are held together by a force which overcomes the repulsion. This force is called

A gravitational force

B electrostatic force

C weak force

D strong force

View Answer

Answer:strong force

14 The mass of a body is 2 kg. It weight is

A 19.6 N

B 20 N

C 30 N

D 40 N

View Answer

Answer:19.6 N

15 A block of mass 2 kg rests on a rough inclined plane making an angle of 30 degree with the horizontal. The coefficient of static friction between he block and the plane is 0.7. The frictional force on the block is

A 9.8 N

B 0.7 × 9.8 × √3 N

C 9.8 × √3 N

D 0.7 × 9.8 N

View Answer

Answer:0.7 × 9.8 N

16 Two bodies of masses 4 kg and 5 kg are acted upon by the same force. If the acceleration of lighter body is 2 m/s², the acceleration of heavier body is

A 1 m/s²

B 1.2 m/s²

C 1.6 m/s²

D 1.8 m/s²

View Answer

Answer:1.6 m/s²

17 Out of the basic forces , gravitational force

A ranks first in strength

B ranks second in strength

C ranks third in strength

D ranks fourth in strength

View Answer

Answer:ranks fourth in strength

18 The frame of reference attached to a satellite of the earth is

A an inertial frame

B an absolute frame at rest with respect to the stars

C a non – inertial frame

D a gravitational frame

View Answer

Answer:a non – inertial frame

19 A block of mass M is placed on a flat surface. A force is applied to move it parallel to the surface. The frictional force f developed is proportional to the

A square of the mass of the body

B mass of the body

C reciprocal of the mass of the body

D reciprocal of the square of the body

View Answer

Answer:mass of the body

20 A particle of mass 0.3 kg is subjected to a force F = -kx with k = 15 N/m. What will be its initial acceleration if it is released from a point 20 cm away from the origin?

A 15 m/s²

B 3 m/s²

C 10 m/s²

D 5 m/s²

View Answer