Question

A tennis ball is thrown from the height h above the ground. If the ball strikes to the ground with elastic collision,what height will height will the ball achieve after the first collision?

• A. $h{e}^6$
• B. $e^{2}h$
• C. $e^{3}h$
• D. none of these

Answer 1

The correct option is B $e^{2}h$

Given,

Initial height = $h$

Coefficient of elasticity, $e\equiv \frac{v_{final}}{v_{inital}}=\sqrt{\frac{K_{final}}{K_{initial}}}=\sqrt{\frac{K_1}{K_0}}$

$K_1=e^2{K}_0$

$mg{h}_1=e^{2}mgh$

$h_1=e^{2}h$

Hence, height after first collision is $e^{2}h$