I have a school project that requires that a penny be launched into a hole. I came up with a crossbow idea, which I wanted to be driven by a rubber band. I have every part built except for the rubber band. The project dictates that I do a motion analysis study to predict if the penny will make it through the hole. I'm unsure of how I would model the rubber band to begin with, and even more unsure of how I would see it work in a motion analysis study. I've included my assembly and parts, if anyone could please give me any insight into this I'd greatly appreciate it.