A man raises a box of mass 50kg to a height of 2m in 20s, while another man raises the same box to the same height in 50s.

(a) Compare: (i) the work done, (ii) the power developed by them.

(b) Calculate the (i) the work done, (ii) the power developed by each man.

Take g = 10N kg^-1.

A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes.

(a) Compare:

(i) the work, and (ii) power developed by them.

(b) How much work each does?

Take density of water = 10³kg m ^-3 and g = 9.8 N kg^-1

The energy possessed by a body due to the force of attraction of earth on it is called its:

1. Rotational kinetic energy
2. Kinetic energy
3. Gravitational potential energy
4. Elastic potential energy

The energy possessed by a body in the deformed state due to change in its size or shape is called:

1. Rotational kinetic energy
2. Kinetic energy
3. Gravitational potential energy
4. Elastic potential energy