MCQ PRACTICE

Welcome to your Ncert – class 9- science – Chapter 8 – Force and Laws of Motion 2

A force of 10 N acts on a ball moving on a surface. The force of friction that must act between the surface of the ball and the surface so that the ball keeps on moving with constant velocity over the surface must be

10 N

Zero

20 N

100 N

None

An Object moving along a straight path with an accelerated motion. The correct statement about the object-

A Its velocity keeps changing

B Its speed keeps changing

C A force is always acting on it

D Its mass keeps on changing

(b) and (c) are correct

All of these

(a) and (b) are correct

(a), (b) and (c) are correct

None

A carpenter exerts a force of magnitude 1.5 N at right angles on the surface of a nail of mass 3 gram to drive it into a wooden plank. If the plank offers a resistive force of 0.6 N and the time of interaction of hammer and the nail 0.01 s, the depth through which the nail penetrates is

15m

1.5 cm

1.5 mm

15 cm

None

Identify the incorrect statement.

Frictional force always acts parallel to the surface of contact.

The weight of a body always acts towards the centre of the Earth.

The spring force always pushes a body.

The tension of a string always pulls a body.

None

Which one is correct if a bullet is fired from a rifle?

There is no motion of bullet and rifle.

Bullet and rifle both move in the backward direction.

Rifle moves in the backward direction and bullet moves in the forward direction.

Bullet moves in the backward direction and rifle moves in the forward direction.

None

If an object moves with a uniform velocity we can conclude that

there is no force acting on the body

no unbalanced force acts on it

an unbalanced force acts on the body

it has uniform acceleration

None

Match the following with correct response.

(1) Action and reaction

(2) Magnitude of force

(3) Momentum

(4) Resultant of balanced force

(A) No acceleration

(B) Newton’s second law

(D) Vector quantity

1-C, 2-B, 3-D, 4-A

1-B, 2-D, 3-A, 4-C

1-D, 2-A, 3-C, 4-B

1-A, 2-C, 3-B, 4-D

None

It is due to which of the following reasons that a scooter generally slips on an oily road?

Friction between tyres and road increases.

All the above.

Friction between tyres and road remain same.

Friction between tyres and road decreases.

None

Which of the following is true about action and reaction forces acting on two bodies of equal masses?

Action and reaction forces are equal and opposite and produce equal and opposite acceleration.

Action and reaction forces are unequal and opposite and produce unequal and opposite acceleration.

Action and reaction forces are unequal and opposite and produce equal and opposite acceleration.

Action and reaction forces are equal and opposite and produce unequal and opposite acceleration.

None

10.

When a force is exerted on an object, it can change its-

A State

B Position

C Shape

D Direction

(b) and (c) are correct

All of these

(a) and (b) are correct

(a), (b) and (c) are correct

None

11.

Two spring balances pull each other in opposite directions. If the reading of one spring balance is 2 N, the reading shown by the second spring balance will be

4 N

2.5 N

2 N

3.5 N

None

12.

The people in a bus are pushed backwards when the bus starts suddenly because of

Inertia due to motion

Inertia due to rest

External force

Inertia due to direction

None

13.

Statement A: Gravitational force is the weakest force in nature.

Statement B: Electrostatic force is an example of non – contact forces.

Which of the above two statements is true?

Statement A is true

Statement B is true

Both the statement a and b are true.

Neither statement A nor B are true

None

14.

Match the following with correct response.

(1) Cause of acceleration

(2) Quantitative measure of inertia

(3) powder applied on carom board

(4) Tyres of vehicles made Rough

(A) Mass

(B) Increases friction

(D) Force

1-B, 2-D, 3-A, 4-C

1-D, 2-A, 3-C, 4-B

1-C, 2-B, 3-D, 4-A

1-A, 2-C, 3-B, 4-D

None

15.

Find the time for which a force of 1kgwt acts on a body of mass 1 kg moving with a uniform speed of 4m/s to stop the body.

0.2 s

0.8 s

0.6 s

0.4 s

None

Chapter 7 - Motion

Chapter 8-Force and Law of Motion

Chapter 9 - Gravitational

Chapter 10 - Work and Energy

CHAPTER 11 - SOUND

Curriculum

NCERT - Class 9 - Science - PHYSICS

Chapter 7 - Motion

Chapter 8-Force and Law of Motion

Chapter 9 - Gravitational

Chapter 10 - Work and Energy

CHAPTER 11 - SOUND

MCQ PRACTICE – 2