# Force And Laws Of Motion MCQ Class 9 Science

Please refer to Chapter 9 Force And Laws Of Motion MCQ Class 9 Science with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 9 Science. Students should refer to MCQ Questions for Class 9 Science with Answers to score more marks in Grade 9 Science exams. Students should read the chapter Force And Laws Of Motion and then attempt the following objective questions.

## MCQ Questions Class 9 Science Chapter 9 Force And Laws Of Motion

The Force And Laws Of Motion MCQ Class 9 Science provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. A body of mass 20 kg moves with an acceleration of 2ms–2. The rate of change of momentum in S.I. unit is –
(A) 40
(B) 10
(C) 4
(D) 1

A

Question. 9.8 N is equal to-
(A) 1 kgf
(B) 1 kgwt
(C) A and B both
(D) Neither A nor B

C

Question. Newton used, ‘quantity of motion’ for-
(A) momentum
(B) force
(C) acceleration due to gravity
(D) none of these

A

Question. A cannon after firing recoils due to –
(A) conservation of energy
(B) backward thrust of gases produced
(C) Newton’s first law of motion
(D) Newton’s third law of motion

D

Question. Newton’s first law of motion is –
(A) qualitative
(B) quantitative
(C) both qualitative and quantitative
(D) neither qualitative nor quantitative

A

Question. When a bus starts suddenly the passengers standing on it, lean backwards in the bus. This is an example of –
(A) Newton’s first law
(B) Newton’s second law
(C) Newton’s third law
(D) none of Newton’s law

A

Question. The law which defines force is –
(A) Newton’s third law
(B) Newton’s first law
(C) Newton’s second law
(D) none of these

Question. An iron ball and aluminium ball has same mass:
(A) inertia of iron is greater than aluminium
(B) both the ball have same inertia
(C) inertia of iron is less than that of Aluminium
(D) none of these

B

Question. If A and B are two objects with masses 10 kg and 30 kg respectively then :
(A) A has more inertia than B
(B) B has more inertia than A
(C) A and B have the same inertia
(D) none of the two have inertia

B

Question. First law of motion defines-
(A) inertia
(B) force
(C) both inertia and force
(D) neither inertia nor force

C

Question. Momentum measures amount of ………… in a body-
(A) inertia
(B) motion
(C) velocity
(D) acceleration

B

Question. Force measures rate of change of ……….. a body
(A) mass
(B) inertia
(C) velocity
(D) momentum

D

Question. Mass measures amount of …………..in a body-
(A) inertia
(B) motion
(C) velocity
(D) acceleration

A

Question. C.G.S. unit of force is –
(A) m/s
(B) s/m
(C) dyne
(D) Newton

C

Question. If a moving ball A collides with another moving ball B, then
(A) momentum of A = momentum of B
(B) (momentum A + momentum of B) before collision = (momentum A + momentum of B) after collision
(C) neither A nor B
(D) A or B both are possible

B

Question. When a bullet is fired from a gun. The gun recoils to –
(A) conserve mass
(B) conserve momentum
(C) conserve K.E
(D) none of these

B

Question. Momentum has same unit as –
(A) impulse
(B) torque
(C) moment of force
(D) couple

A

Question. When force of 1 N acts on mass of 1 kg, whichis able to move freely, the object moves with a/an –
(A) speed of 1 ms–1
(B) speed of 1 kms–1
(C) acceleration of 10 ms–2
(D) acceleration of 1 ms–2

D

Question. The net force acting on a body of mass of 1 kg moving with a uniform velocity of 5 ms–1 is –
(A) 5 N
(B) 0.2 N
(C) 0 N
(D) None of these

C

Question. A body of mass M strikes against wall with a velocity v and rebounds with the same velocity. Its change in momentum is –
(A) zero
(B) Mv
(C) –Mv
(D) –2 Mv

D

Question. Gram weight is a unit of-
(A) mass
(B) weight
(C) A and B both
(D) neither A nor B

B

Question. A body of mass 5 kg undergoes a change in speed from 20 m/s to 0.20 m/s. The momentum-
(A) increases by 99 kgm/s
(B) decreases by 99 kgm/s
(C) increases by 101 kgm/s
(D) decreases by 101 kgm/s

B

Question. Choose correct relation :
(A) a = F/m
(B)aF = m
(C) m = F × a
(D) none of these

A

Question. Inertia of rest is the property by virtue of which
the body is unable to change by itself:
(A) the state of rest only
(B) the state of uniform linear motion
(C) the direction of motion only
(D) the steady state of rest

D

Question. A bullet in motion hits and gets embedded in a solid resting on a frictionless table. What is conserved ?
(A) Momentum and K.E.
(B) Momentum alone
(C) K.E. alone
(D) None of these

B

Question. Choose correct statement-
(A) Action and reaction forces act on same object.
(B) Action and reaction forces act on different objects.
(C) A and B both are possible.
(D) Neither A nor B is correct.

B

Question. The combined effect of mass and velocity is taken into account by a physical quantity called
(A) torque
(B) moment of force
(C) momentum
(D) all of them

C

Question. How many dynes are equal to 1 N ?
(A) 106
(B) 104
(C) 105
(D) 103

C

Question. A bullet of mass 0.01 kg is fired from a gun weighing 5.0 kg. If the initial speed of the bullet is 250 m/s, calculate the speed with which the gun recoils-
(A) – 0.50 m/s
(B) – 0.25 m/s
(C) + 0.05 m/s
(D) + 0.25 m/s

A

Question. A man is standing on a boat in still water. If he walks towards the shore the boat will –
(A) move away from the shore
(B) remain stationary
(C) move towards the shore
(D) sink