Question

A ball kept at a height of $5$m, is allowed to fall freely. It hits the ground. The coefficient of restitution is $0.6$ What is the time interval between the first nd second rebound?($g=10m/s^2$)

• A. $1s$
• B. $1.1s$
• C. $1.25s$
• D. $1.5s$

Answer 1

The correct option is C $1.25s$

Let $u$ be the velocity of striking.

$e=6.0$

$u_{Bgf}=e$

$u_{Bgf}=0.6\times 10$

$u_{Bgf}=6m/s$

$u_{Bgi}=2\times 5\times g$

$u_{Bgi}=10m/s$

Time taken for second rebound

$0=6t-\frac{1}{2}g{t}^2$

$0=t(6-5t)$

$t=1.25$