Question

A ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of

• A. 16/25
• B. 44597
• C. 44625
• D. 44806

Answer 1

The Correct Option is B

Using, $\upsilon^2 - u^2 = 2gh$, we get $\upsilon = \sqrt{2gh}$ $\therefore\,\frac{\upsilon_2}{\upsilon_1} = \sqrt{\frac{h_2}{h_1}} = \sqrt{\frac{1.8}{5}} = \frac{3}{5}$
Loss in velocity = $\frac{\upsilon_1 - \upsilon_2}{\upsilon_1} = \upsilon_1 - \frac{\upsilon_2}{\upsilon_1} = 1 - \frac{3}{5} = \frac{2}{5}$