How do I build a catapult that launches a tennis ball 100 ft?

Al: How do I build a catapult that launches a tennis ball 100 ft?
For my physics class, we are supposed to build a catapult to launch a tennis ball a tennis ball as far as possible. We can not use any slingshot designs. Can you point me in the direction of what type I should build? Thanks.

Answers and Views:

Answer by $ andman
trebuchet

Answer by Franky
look how the romans built their catapults without a sling. If you built it the same way, you’ll bring the tennis ball even more than 100 feet apart from the catapult.

Franky

Answer by Peter Green
lots of springs