Book: #2

Question to consider before viewing this film:

Imagine that one billiard ball collides head on with another billiard ball. After the impact, the first ball is at rest and the second ball moves away with the same velocity that the first ball had initially. Would the same observation be true if one of the billiards Balls were made of steel and the other made of iron? 
     (Consider the balls to be of the same mass and size.)