In the figure,determine the type of collision. The masses of the blocks,and the velocities before and after the collision are given. The collision is

$A$ ball initially at rest is hit by another identical ball moving with some velocity as shown. Find the angle $\theta_2$ if the surface is without friction and the collision is perfectly elastic. $......^{\circ}$

$A$ ball of mass $m$ moving with speed $u$ undergoes a head-on elastic collision with a stationary ball of mass $nm$. What is the fraction of the kinetic energy transferred to the heavier ball?

In the elastic collision of objects,

There are $n$ elastic balls placed on a smooth horizontal plane. The masses of the balls are $m, \frac{m}{2}, \frac{m}{2^2}, \ldots, \frac{m}{2^{n-1}}$ respectively. If the first ball hits the second ball with velocity $v_0$,then the velocity of the $n^{\text{th}}$ ball will be,

$A$ molecule of mass $m$ moving with velocity $v$ makes $5$ elastic collisions with a wall of a container per second. The change in momentum of the wall per second in $5$ collisions will be: