How does the speed of an incoming pitch affect the speed of a baseball after it's hit?

Which will go further if a batter manages to hit it with a baseball bat: a baseball thrown to the batter at 90 miles per hour or one thrown at 60 miles per hour?

-

The faster ball will recoil faster, because the collision is partially elastic. The ball compresses at contact with the bat, and the outgoing velocity is faster than the bat velocity by the effect of the compression, which is always increasing with the incoming speed. So all else being equal, the faster ball recoils faster.

There are no confounding factors. There are no extra variables. This is just the answer.

-

This all depends on the ball, the air pressure, the batter, his bat, and a whole bunch of other variables, including some that can't be controlled. Otherwise, there is no real way to scientifically determine which pitch speed will cause the hit to go farther/faster.

-
Unless the bat breaks, the players start playing underwater, or the player suddenly gets turned to jello, the answer is always that the 60mph baseball goes faster than the 50mph. – Ron Maimon Dec 22 '11 at 5:13
No, not necessarily. What you are saying is that the swing is always the same, ALWAYS, and that means a variable you cannot control, not to mention others. – fr00ty_l00ps Dec 22 '11 at 15:09
not my downvote, but the question presumes that the swing is the same and the impact point the same. There are no variables you cannot control, this is not the humanities. – Ron Maimon Dec 22 '11 at 19:00
Otay, I understand now. – fr00ty_l00ps Dec 22 '11 at 19:02