The catapult dates back to medieval times when wise men of the era realized they could launch large objects a great distance without much effort. The physics lay in the storage of energy in some system, in this case, the catapult. In some cases a counter weight was used to launch a payload, whereas in other cases and as is the case in my project, sturdy rope was wound against itself. In trying to return to an equilibrium point, like a spring, the rope tries to unwind itself and in the process has a tremendous amount of velocity. This can be used to launch a payload many meters as I found out, at the expense of an overhead projector and a couple of light fixtures (oops!!). Who says science isn’t exciting!!!
Many different designs were used, however the one I chose to use for this project consisted of a simple frame and a swing arm mounted between 2 ropes. The system was wound up and restrained so the arm would travel about 90 degrees and hit an arrestor bar and release its payload.
Winding the arm of the catapult.