So I think i should probably open this by saying that our catapult broke, and by broke i mean careened out of control toward my face. That aside i thoroughly enjoyed building a catapult except for the part where PVC primer spilled all over my driveway. The physics of our catapult was to the say the least interesting. As it was made of PVC it required very little weight in order to create sufficient energy to launch a softball. The way we realized this was by seeing that 20 pounds was more than sufficient to cause the catapult to move with an extreme velocity and then immediately shatter from the stress, because PVC is literally weaker than most sticks. Given how weak our PVC was and how little weight was attached to it you'd think the counterweight in our release mechanism would be rather low, nope it required sixty pounds to hold down along with another 40 pounds stabilizing the frame of the catapult. Apparently PVC just exists to make life miserable. On that train of thought PVC cement should be called PVC disappointment, that useless malarkey withstood like 20 newtons of force and then called it a day. I'm gonna end this by briefly readdressing the catapult that came toward my face, our catapult was designed to function in an ideal environment that wind was so less than ideal so basically i blame the wind entirely for our catapult not going a hundred yards and instead going for my face, nothing else could have sabotaged that, definitely not suspect construction that could only withstand a minimal velocity or weight.