$A$ bullet of mass $a$ moving with velocity $b$ strikes a block of mass $c$ and gets embedded in it. Find the velocity of the block.

$A$ particle of mass $m$ moving in the $x$ direction with speed $2v$ is hit by another particle of mass $2m$ moving in the $y$ direction with speed $v$. If the collision is perfectly inelastic,the percentage loss in the energy during the collision is close to $..........\%$

$A$ particle of mass $m$ moving in the $x$-direction with speed $2v$ is hit by another particle of mass $2m$ moving in the $y$-direction with speed $v$. If the collision is perfectly inelastic,the percentage loss in the energy during the collision is close to .............. $\%$

$A$ neutron of mass $1.67 \times 10^{-27} \ kg$ moving with a velocity of $10^8 \ m/s$ collides with a deuteron at rest and sticks to it. If the mass of the deuteron is $3.34 \times 10^{-27} \ kg$,what will be the velocity of the combined system?

$A$ 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 $km/h$?

$A$ bullet strikes a solid block resting on a frictionless horizontal table and gets embedded in it. Which of the following is conserved?