The weight of a person on a planet
Question:

The weight of a person on a planet $\mathrm{A}$ is about half that on the earth. He can jump upto $0.4 \mathrm{~m}$ height on the surface of the earth. How high he can jump on the planet $A$ ?

Solution:

P.E. of person at height $h_{1}$ on earth $=$ P.E. at height $h_{2}$ on planet i.e. $m g_{e} h_{1}=m g_{p} h_{2}$ or $h_{2}=\left(g / g_{p}\right) h_{1}=\left(\frac{g_{e}}{g / 2}\right) \times 0.4 \mathrm{~m}=0.8 \mathrm{~m}$.