$A$ rubber ball is dropped from a height of $5 \ m$ on a planet where the acceleration due to gravity is unknown. After bouncing,the ball reaches a height of $1.8 \ m$. What fraction of its velocity does the ball lose upon impact?

Ball $P$ of mass $m$ moving with velocity $v$ collides with another ball $Q$ of mass $2m$, which is at rest. If $v_P$ and $v_Q$ are the final velocities of $P$ and $Q$ respectively after the collision, then (Assume the coefficient of restitution is $e = 1/3$):

In the figure shown,a small ball hits obliquely a smooth and horizontal surface with speed $u$ whose $x$ and $y$ components are indicated. If the coefficient of restitution is $\frac{1}{2}$,then its $x$ and $y$ components $v_x$ and $v_y$ just after collision are respectively

$A$ ball of mass $m$ strikes a smooth ground at an angle $\alpha$ as shown in the figure and is deflected at an angle $\beta$. The coefficient of restitution will be

$A$ ball is dropped from a height $h$. It bounces repeatedly. Find the height attained by the ball after $n$ bounces and the time taken by the ball to complete $n$ bounces.

The quantity that is not conserved in an inelastic collision is