Thanks Delphi51 for that insight. But since I need to fire a tennis ball some 12 meters, I would need a much stronger spring than one that shots off a marble. Do you guys know where I could get a spring with a lot of potential energy. Also, if you guys have any other ideas as to how a different...
For my Physic class, my teacher assigned us with a project of creating a mechnical cannon, meaning no human, electrical, chemical, pneumatic energy can be applied. I was wondering if you guys have any idea of the type of mechnical mechanism that I should use to fire tennis at both a 8 m and 12 m...