An object falls from a height of 10 m above the ground. After striking the ground it loses 50% of its kinetic energy. The height upto which the object can rebounce from the ground is:

A 7.5 m

B 10 m

C 2.5 m

D 5 m

The answer is D.

Solution

KE before striking ground: $K_1=mgh_1=mg(10)$. After losing 50%, $K_2=\dfrac{1}{2}K_1=mg(5)$. Since $K_2=mgh_2$, $h_2=5$ m.

Concept Energy conservation in free fall and rebound

71 questions from this chapter have appeared across 27 exam years.