A box of mass 300 kg has gravitational potential energy stored in it equal to 29400 J. Find the height of the box above the ground.

(Take g = 9.8 N kg^-1)

A body of mass 10 kg falls from a height of 20 m to 8 m.

Calculate:

(i) the loss in potential energy of the body,

(ii) the total energy possessed by the body at any instant? (Take g = 10 ms^-2).

A boy weighing 50 kgf climbs up from the first floor at a height of 3 m above the ground to the third floor at a height of 9 m above the ground. What will be the increase in his gravitational potential energy?

(Take g = 10 N kg^-1).

A vessel containing 50 kg of water is placed at a height 15m above the ground. Assuming the gravitational potential energy at the ground to be zero, what will be the gravitational potential energy of water in the vessel?

(g = 10ms^-2).