Question

a man weighing 50 kg lifts a weight of 30 kg to the top building 10 m high. find the work done by him. (take g = 9.8ms^-2)

Answer 1

$$\begin{gathered} \mathrm{Total}\mathrm{mass}: \\ \mathrm{m}=50+30=80\mathrm{kg} \\ \mathrm{Height}: \\ \mathrm{h}=10\mathrm{m} \\ \mathrm{Work}\mathrm{done}: \\ \mathrm{W}=\mathrm{Potential}\mathrm{energy} \\ =\mathrm{mgh} \\ =80\times 9.8\times 10 \\ =7840\mathrm{J} \end{gathered}$$