Tenis Game, Ball Height Effect and Baseball effect

I’m new in making Flash Games. So i played something like this:

http://www.gamedesign.jp/flash/tennis/tennis.html

I’m wondering how to create an effect, of different tennis ball height. When ball is hitted, for a second its height is raising, and then going down. Maybe someone could help me with that?

Second question is about in this game:

And effect when pitcher is throwing a ball, and it is getting closer but i don’t have any idea how it is made.