Question

What is the potential energy of a stone
of mass 10 kg that is lifted to a height
of 8 m, if g = 10 N kg-1 ?​

Answer 1

Work done is change in potential energy of the object. Here the assumption is that the force which lifts the body, balances the weight at all times, meaning which there is no linear velocity of the object during this motion.

All the work done by the force is reflected as the increase in the stored potential energy of the object. Potential energy is defined as a difference of potential energy between two reference points and

U2 - U1 = mgh = 10 * 10 * 5 = 500 N-m

So the work done =Change in potential energy= 500 Nm.

Answer 2

Given - Mass - 10 kg

Acceleration due to gravity - 10 N/kg or 10 m/s²

Height - 8 metre

Find - Potential energy of stone.

Solution - To find potential energy of a stone, formula used is - m*g*h. In the formula, m is mass, g represents acceleration due to gravity and h refers to height.

Keeping the values in equation-

Potential energy - 10*10*8

Potential energy - 800 J.

Hence, the potential energy of a stone is 800 J.