A body of mass 'm' moving with certain velocity collides with another identical body at rest. If the collision is perfectly elastic and after the collision both the bodies moves

A body of mass 20 gm is moving with a certain velocity. It collides with another body of mass 80 gm at rest. The collision is perfectly inelastic. The ratio of the kinetic energies before and after collision of the system is

A billiard ball of mass M , moving with velocity v_1 collides with another ball of the same mass but at rest . If the collision is elastic , the angle of divergence after the collision is

Body A of mass 4m moving with speed u collides with another body B of mass 2m at rest the collision is head on and elastic in nature. After the collision the fraction of energy lost by colliding body A is :