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

$A$ mass $M$ moving with velocity $V$ along the $x$-axis collides and sticks to another mass $2M$ which is moving along the $y$-axis with velocity $3V$. The velocity of the combination after the collision is:

$A$ body of mass $m$ moves with velocity $v$ in the East direction,and another body of the same mass moves with velocity $v$ in the North direction. After they collide and stick together,what is the combined velocity of the resulting body of mass $2m$?

$A$ 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 $..........\%$

$A$ bullet of mass $m$ and velocity $v$ when fired at a sand bag of mass $M$,suspended by a string,gets embedded into the bag. The loss of kinetic energy in this process is

$A$ body of mass $m$ is moving with velocity $u$ as shown in the figure and it collides with a body of mass $4m$ at rest. If the collision is perfectly inelastic,then the percentage loss in kinetic energy is: