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?

Difficulty: Easy
A:

Force

B:

Net force

C:

Mass

D:

Velocity

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

Difficulty: Easy
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?

Difficulty: Easy
A:

Zero

B:

5N

C:

10 N

D:

20N

The mass of a body?

Difficulty: Easy
A:

Decreases when accelerated

B:

Increases when accelerated

C:

Decreases when moving with high velocity

D:

None of the above

Two bodies of masses $m_{1}$ and $m_{2}$ 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?

Difficulty: Hard
A:

$\frac{[(m_{1} \times m_{2})}{(m_{1} +m_{2})]}g$

B:

$\frac{[(m_{1} - m_{2})}{(m_{1} +m_{2})]}g$

C:

$\frac{[(m_{1} + m_{2})}{(m_{1} - m_{2})]}g$

D:

$\frac{[(2m_{1} m_{2})}{(m_{1} + m_{2})]}g$

Which of the following is the unit of momentum?

Difficulty: Medium
A:

Nm

B:

$kgm^{-1}$

C:

Ns

D:

$Ns^{-1}$

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

Difficulty: Easy
A:

Cart

B:

Earth

C:

Horse

D:

Earth and cart

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

Difficulty: Easy
A:

Water

B:

Fine marble powder

C:

Air

D:

Oil