Originally Posted by sureshs
What had really amazed me was observing old short men hitting down on the ball and getting the flat serve in (with a very good percentage, honed over the years). These guys would not know top spin even if it crawled up their behinds. That is what led me to look into the (wrong) geometrical proof that has been around all these years claiming that you have to be 9 feet tall or whatever to put the ball into the box if you hit down. It was simply a lack of knowledge of the parabolic shape of projectile motion (exact without air drag, approximate with air drag).
by parabolic, do you mean "round/curved"? I don't speak physics that well.