Q. A ball is allowed to fall from a height of $10\ m$. If there is 40% loss of energy due to impact, then after one impact ball will go up to
A) $10\ m$
B) $8\ m$
C) $4\ m$
D) $6\ m$
Explanation
(d) $mgh =$ initial potential energy
$mgh^{'} =$ final potential energy after rebound
As 40% energy lost during impact
$\therefore mgh^{'} = 60\%$ of $mgh$
$\Rightarrow h^{'} = \frac{60}{100} \times h = \frac{60}{100} \times 10 = 6m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.