Physics 9-Ch3 (Dynamics)-MCQs

 

Table of Contents

• Newton's first law of motion is valid only in the absence of?
• Does inertia depend upon?
• A boy jumps out of a moving bus. There is a danger of him falling?
• A string is stretched by two equal and opposite forces of 10 N each. The tension in the string is?
• The mass of a body
• Two bodies of masses m1 and m2 are attached to the ends of an inextensible string passing over a frictionless pulling such that both move vertically
• Which of the following is the unit of momentum
• When a horse pulls a cart, the action is on the
• Which of the following material lowers friction when pushed between metal plates

Newton's first law of motion is valid only in the absence of? 

Difficulty: Easy

A:

Force

B:

Net force

C:

Friction 

D:

Momentum

Does inertia depend upon?

A:

Force

B:

Net force

C:

Mass

D:

Velocity 

A boy jumps out of a moving bus. There is a danger of him falling?

A:

Towards the moving bus

B:

Away from the bus

C:

In the direction of motion

D:

Opposite to the direction of motion

A string is stretched by two equal and opposite forces of 10 N each. The tension in the string is?

A:

Zero

B:

5N

C:

10 N

D:

20N

The mass of a body?

A:

Decreases when accelerated

B:

Increases when accelerated

C:

Decreases when moving with high velocity

D:

None of the above

Two bodies of masses ${�}_1$ and ${�}_2$ are attached to the ends of an inextensible string passing over a frictionless pulling such that both move vertically. The acceleration of the bodies is?

A:

$\frac{[({�}_1\times {�}_2)}{({�}_1+{�}_2)]}�$

B:

$\frac{[({�}_1-{�}_2)}{({�}_1+{�}_2)]}�$

C:

$\frac{[({�}_1+{�}_2)}{({�}_1-{�}_2)]}�$

D:

$\frac{[(2{�}_1{�}_2)}{({�}_1+{�}_2)]}�$

Which of the following is the unit of momentum?

A:

Nm

B:

$��{�}^{-1}$

C:

Ns

D:

$�{�}^{-1}$

When a horse pulls a cart, the action is on the?

A:

Cart

B:

Earth

C:

Horse

D:

Earth and cart

Which of the following material lowers friction when pushed between metal plates?

A:

Water

B:

Fine marble powder

C:

Air

D:

Oil