Two balls of mass $5 \ kg$ are moving in opposite directions with the same speed of $5 \ m/s$. They undergo a head-on elastic collision. Find the final velocity of the balls in $m/s$.

$A$ heavy steel ball of mass greater than $1\, kg$ moving with a speed of $2\, m/s$ collides head-on with a stationary ping-pong ball of mass less than $0.1\, g$. The collision is elastic. After the collision,the ping-pong ball moves approximately with a speed of ......... $m/s$.

The coefficient of restitution for a perfectly elastic collision is

Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed $V$. If the collision is elastic,which of the following figure is a possible result after collision?

Assertion $(A)$: In an elastic collision of two billiard balls,both kinetic energy and linear momentum remain conserved.
Reason $(R)$: During the collision of the balls,as the collision is elastic,there is no exchange of energy. Therefore,both energy and momentum are conserved.

$A$ smooth sphere $A$ is moving on a frictionless horizontal plane with an angular speed $\omega$ and its center of mass has a linear velocity $v$. It undergoes an elastic collision with an identical sphere $B$,which is initially at rest. After the collision,their angular speeds are $\omega_A$ and $\omega_B$ respectively. Neglecting friction,which of the following is true?