$A$ metal ball of mass $2 \,kg$ moving with a velocity of $36 \,km/h$ has a head-on collision with a stationary ball of mass $3 \,kg$. If after the collision,the two balls move together,the loss in kinetic energy due to the collision is ........ $J$.

$A$ body of mass $2\, kg$ moving with a velocity of $3\, m/s$ collides head-on with a body of mass $1\, kg$ moving in the opposite direction with a velocity of $4\, m/s$. After the collision,the two bodies stick together and move with a common velocity. The common velocity in $m/s$ is equal to:

$A$ 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 $\,ms^{-1}$)

Two identical balls are suspended side by side by two long strings. One ball is pulled aside so that its center of gravity rises by a vertical distance $h$. It is then released and undergoes a perfectly inelastic collision with the other ball. What is the vertical distance to which the center of gravity of the combined system rises?

Statement $1$: In a perfectly inelastic collision,the total energy of two particles moving in the same direction is not completely lost.
Statement $2$: The principle of conservation of momentum is valid for all types of collisions.

Two bodies $A$ and $B$ of same mass undergo a completely inelastic one-dimensional collision. The body $A$ moves with velocity $v_1$ while body $B$ is at rest before the collision. The velocity of the system after the collision is $v_2$. The ratio $v_1: v_2$ is