[Al Skierkiewicz]

Now that I have thought about this for a day I can see that there is a lot of energy transferred to surface when the balls strike. Taking Chris's explanation of the center of percussion, when equal diameter balls collide on an infinitely strong surface, something has to give and you would expect that the balls would lift off the table momentarily. Then looking at the dynamics of two low friction surfaces meeting at relatively high pressure (the collision) then force must be transferred to the ball at rest in a downward direction due to the the rotation of the moving ball. It would interesting to run this experiment in a weightless environment. Thanks for the explanation guys.