The catapult project obviously has a lot of phyisics attatched to it. When we tested our catapult, we had some trouble getting it to go forward instead of backward. We where able to fix it by modifying our throwing mechanism to accomodate a ball. What we did not account for, however, was that the baseball we where useing in place of a softball was not the same size or weight as an acctuall softball. Because of this, we could only get the softball to acctually go forward once on test day. what we should have done was make a better throwing mechanism and acctually bought a softball to do a test with.