$A$ $1 \ kg$ ball moving with a speed of $6 \ ms^{-1}$ collides head-on with a $0.5 \ kg$ ball moving in the opposite direction with a speed of $9 \ ms^{-1}$. If the coefficient of restitution is $\frac{1}{3}$,then the energy lost in the collision is (in $J$)

$A$ mass $m$ moves with a velocity $v$ and collides inelastically with another identical mass at rest. After the collision,the $1^{st}$ mass moves with velocity $\frac{v}{\sqrt{3}}$ in a direction perpendicular to the initial direction of motion. Find the speed of the $2^{nd}$ mass after the collision.

$A$ body is dropped on the ground from a height $h_1$ and after hitting the ground,it rebounds to a height $h_2$. If the ratio of velocities of the body just before and after hitting the ground is $4$,then the percentage loss in kinetic energy of the body is $\frac{x}{4}$. The value of $x$ is $.......$

$A$ ball hits the floor and rebounds after an inelastic collision. In this case:

$A$ ball is allowed to fall freely from a height of $42 \ m$ from the ground. If the coefficient of restitution between the ball and the ground is $0.4$,then the total distance travelled by the ball before it comes to rest is (in $m$)

$A$ ball kept at $20 \,m$ height falls freely in a vertically downward direction and hits the ground. The coefficient of restitution is $0.4$. What is the velocity of the ball after the first rebound (in $\,ms^{-1}$)? $\left[g=10 \,ms^{-2}\right]$