A billiard ball of mass .155 kg moves with a velocity of 12.5 m/s toward a stationary billiard ball of identical mass and strikes it in a head on collision. The first billiard ball comes to a complete stop. Was the collision elastic?
Suppose,a ball of mass
Let,after the collision velocity of the 2nd mass will be
So,applying law of conservation of momentum,
so,kinetic energy before the collision =
and after the collision,kinetic energy became =
So,kinetic energy before and after the collision remains the same.
Hence it was an elastic collsion.
Remember,in an elastic collsion,two identical mass just exchange their velocity.
And,coefficient of restitution is