Hey, for a physics project, i have the task of building a manpowered cart that will fit one person in and slingshoot a regular volleyball a whopping 8-10m! the basic plan so far is to have the cart approximately 5'3 in length and just wide enough to fit the person it. The task is to hit a target composed of a pile of buckets that need to be knocked down. it's been found that in order to have the most powerful force, the slingshot must be positioned at forty five degrees. any ideas on what material could be used to make the slingshot, or how? ideas appreciated!