Velocity of the ball $A$ after collision with the ball $B$ as shown in the figure is ............. $m/s$. (Assume perfectly inelastic and head-on collision)

$A$ bag of mass $M$ is suspended by a string. $A$ bullet of mass $m$ moving with velocity $v$ enters the bag and gets embedded in it. Then,for the system:

$A$ 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 $2m$?

$A$ 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

$A$ body of mass $3 \,kg$ is moving with a velocity of $8 \,ms^{-1}$ collides head-on with another body of mass $1 \,kg$, moving in the opposite direction with a velocity of $4 \,ms^{-1}$. After the collision, if the two bodies stick together and move, they move with a common velocity: (in $\,ms^{-1}$)