$A$ mass $m_1$ moves with a great velocity. It strikes another mass $m_2$ at rest in a head-on collision. It comes back along its path with low speed after the collision. Then:

$A$ neutron with velocity $v$ strikes a stationary deuterium atom. By what factor does its kinetic energy change?

Consider an elastic collision of a particle of mass $m$ moving with a velocity $u$ with another particle of the same mass at rest. After the collision, the projectile and the struck particle move in directions making angles $\theta_1$ and $\theta_2$ respectively with the initial direction of motion. The sum of the angles, $\theta_1 + \theta_2$, is equal to: (in $^\circ$)

In an elastic collision of two billiard balls,which of the following quantities remain conserved during the short time of collision of the balls? (i.e.,when they are in contact)
$(a)$ Kinetic energy.
$(b)$ Total linear momentum.
Give reason for your answer in each case.

The bob $A$ of a simple pendulum is released when the string makes an angle of $45^{\circ}$ with the vertical. It hits another bob $B$ of the same material and same mass kept at rest on the table. If the collision is elastic,what happens after the collision?

$A$ billiard ball moving with a speed of $5 \, m/s$ collides with an identical ball originally at rest. If the first ball stops after collision,then the second ball will move forward with a speed of ........... $m/s$.