$A$ body of mass $m$ moving with a constant velocity $v$ hits another body of the same mass that is at rest. If the two bodies stick together after the collision,the velocity of the compound body is:

$A$ moving body of mass $m$ and velocity $3 \, km/h$ collides with a body of mass $2m$ at rest and sticks to it. Now the combined mass starts to move. What will be the combined velocity in $km/h$?

Two balls of masses $m$ each are moving at right angles to each other with velocities $6 \, m/s$ and $8 \, m/s$ respectively. If the collision between them is perfectly inelastic,the velocity of the combined mass is ......... $m/s$.

$A$ neutron having a mass of $1.67 \times 10^{-27} \ kg$ and moving at $10^8 \ m/s$ collides with a deuteron at rest and sticks to it. If the mass of the deuteron is $3.34 \times 10^{-27} \ kg$,then the speed of the combination is:

Find the correct option based on the two statements given below.
Statement-$1$ : Two particles moving in the same direction do not lose all their energy in a perfectly inelastic collision.
Statement-$2$ : The law of conservation of linear momentum is obeyed for all types of collisions.

The coefficient of restitution $e$ for a perfectly inelastic collision is