A billiard ball moving to the left at 30 cm/s collides head on with another billiard ball moving to the right at 19 cm/s. The masses of the balls are...

A billiard ball moving to the left at 30 cm/s collides head on with another billiard ball moving to the right at 19 cm/s. The masses of the balls are identical. If the collision is perfectly elastic, what is the velocity of each ball after the impact?

vf, initially at 30 cm/s =          cm/s

vf, initially at 19 cm/s =           cm/s