Question

A man weighing $50kg$ climbs up a vertical height of $100m$. Calculate the amount of work done by him. How much P.E. does he gain?

Answer 1

Step 1: Given data

$$\begin{gathered} Massofboy,\mathrm{m}=50\mathrm{kg} \\ Height,\mathrm{h}=100\mathrm{m} \end{gathered}$$

Step 2: Find the potential energy gained by the boy

Since the boy does not move anything with his force, the work done by him is zero

Work done on the boy = gain in potential energy.

$$\begin{gathered} \mathrm{P}.\mathrm{E}=\mathrm{mgh} \\ \mathrm{P}.\mathrm{E}=50\times 9.8\times 100 \\ \mathrm{P}.\mathrm{E}=49\mathrm{KJ} \end{gathered}$$

Hence, potential energy gained by a boy is $\mathbf{49}\mathit{K}\mathit{J}$.