Posted by Elizabeth on .
Two billiard balls with identical masses and sliding in opposite directions have an elastic headon collision. Before the collision, each ball has a speed of 20 cm/s. Find the speed of each billiard ball immediately after the collision.

Physics 
Damon,
momentum (total of zero) and energy (total of 2*(1/2) m v^2) are conserved. Therefore each rebounds at original speed but opposite direction.