Q. If a ball is dropped from rest, its bounces from the floor. The coefficient of restitution is 0.5 and the speed just before the first bounce is 5$ms^{- 1}$. The total time taken by the ball to come to rest is
A) 2 s
B) 1 s
C) 0.5 s
D) 0.25 s
Explanation
(c) Acceleration $a = \frac{v - u}{t}$
Or $a = \frac{v - v_{0}}{t}$
Or $g = \frac{v - v_{0}}{t}$
$\therefore\ \ \ v = 0$
Speed before first bounce
$v_{0} = - 5ms^{- 1}$
$\therefore\ \ t = \frac{v_{B} - v_{A}}{g} = \frac{0( - 5)}{10} = \frac{5}{10} = 0.5$ s
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.