$A$ body of mass $1\,kg$ collides head-on elastically with a stationary body of mass $3\,kg$. After the collision,the smaller body reverses its direction of motion and moves with a speed of $2\,m/s$. The initial speed of the smaller body before the collision is $..........\,m/s$.

When two particles collide elastically,then impulsive force can't change

The bob of a simple pendulum (mass $m$ and length $l$) is dropped from a horizontal position. It strikes a block of the same mass $m$ placed on a horizontal frictionless table. The collision is elastic. The kinetic energy of the block after the collision will be

$A$ moving particle of mass $m$ makes a head-on elastic collision with another particle of mass $2m$ which is initially at rest. The percentage loss in energy of the colliding particle on collision is close to .................. $\%$

As per the given figure,a small ball $P$ slides down the quadrant of a circle and hits another ball $Q$ of equal mass which is initially at rest. Neglecting the effect of friction and assuming the collision to be elastic,the velocity of ball $Q$ after the collision will be $............\,m/s$ $(g = 10\,m/s^2)$.

When two bodies collide elastically,then