A rubber ball is dropped from a height of 20 m on a plane. On bouncing it rises to 5 m. The ball los

Question

A rubber ball is dropped from a height of 20 m on a plane. On bouncing it rises to 5 m. The ball loses its velocity on bouncing by a factor of

Professor PC Thomas Classes · Answer

(a) : The velocity just before impact is $v_1 = \sqrt{2gh_1} = \sqrt{2 	imes 10 	imes 20} = 20 \mathrm{~m/s}$. The velocity just after bouncing is $v_2 = \sqrt{2gh_2} = \sqrt{2 	imes 10 	imes 5} = 10 \mathrm{~m/s}$. Loss in velocity is $\Delta v = v_1 - v_2 = 20 - 10 = 10 \mathrm{~m/s}$. The factor by which it loses velocity is $\frac{\Delta v}{v_1} = \frac{10}{20} = \frac{1}{2}$.