You lift a suitcase from the floor and keep it on a table. The work done by you on the suitcase does not depend on:

a.	the path is taken by the suitcase
b.	the time is taken by you in doing so
c.	the weight of the suitcase
d.	your weight

Choose the correct option:

1.	(a), (b) and (d)
2.	(b), (c) and (d)
3.	(a), (c) and (d)
4.	all of these

No work is done by a force on an object if:

Choose the correct option:

A particle of mass m is attached to a light string of length I, the other end of which is fixed. Initially, the string is kept horizontal and the particle is given an upward velocity v. The particle is just able to complete a circle.

(a) The string becomes slack when the particle reaches its highest point.

(b) The velocity of the particle becomes zero at the highest point.

(c) The kinetic energy of the ball in its initial position was \(\frac{1}{2}mv^2 = mgl.\)

(d) The particle again passes through the initial position.

Choose the correct option:

1. (a) and (b)

2. (b) and (c)

3. (c) and (d)

4. (a) and (d)

The kinetic energy of a particle continuously increases with time. Then we can conclude that:

Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (b) and (d)
4. (c) and (d)

One end of a light spring of spring constant k is fixed to a wall and the other end is tied to a block placed on a smooth horizontal surface. In a displacement, the work done by the spring is \(\frac{1}{2}\)kx². The possible causes are

(a) the spring was initially compressed by a distance and was finally in its natural length

(b) it was initially stretched by a distance of x and was in its natural length

(b) it was initially in its natural length and finally in the compressed position

(d) it was initially in its natural length and finally in a stretched position

Choose the correct option:

1. (a) and (b)

2. (b) and (c)

3. (c) and (d)

4. All of these

A block of mass M is hanging over a smooth and light pulley through a light string. The other end of the string is pulled by a constant force F. The kinetic energy of the block increases by 20 J in 1 s.

1. The tension in the string is Mg

2. The tension in the string is F

3. The work done by the tension on the block is 20 J in the above 1 s

4. The work done by the force of gravity is –20 J in tie above 1 s

A bullet hits a block kept at rest on a smooth horizontal surface and gets embedded into it. Which of the following does not change?

A ball kept in a closed box moves in the box making collisions with the walls. The box is kept on a smooth surface. The velocity of the centre of mass:

A body at rest breaks into two pieces of equal masses. The parts will move:

The quantities remaining constant in a collision are: