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

$A$ particle of mass $m$ moving with velocity $v$ collides with a stationary particle of mass $2m$ and sticks to it. What will be the speed of the system?

$A$ body of mass $2 \, kg$ moving with a velocity $(\hat{i} + \hat{j} + \hat{k}) \, m/s$ collides with another body of mass $5 \, kg$ moving with velocity $(\hat{i} - 2\hat{j} + 3\hat{k}) \, m/s$. If they stick together,the velocity (in $m/s$) of the composite body is:

$A$ body of mass $10 \, kg$ moving with a speed of $3 \, m/s$ collides with another stationary body of mass $5 \, kg$. As a result,the two bodies stick together. The $KE$ of the composite mass will be .......... $J$.

$A$ bag of mass $M$ is suspended by a long string. $A$ bullet of mass $m$ moving with velocity $v$ hits the bag and gets embedded in it. For the (bag + bullet) system:

$A$ bullet of mass $a$ and velocity $b$ is fired into a large block of mass $c$. The final velocity of the system is