The goal of this project was to fire an object as far as we could using a catapult or trebuchet. The restrictions to this project was that the trebuchet could not be over a meter in any dimension. It also had to sit on the ground and it had to have a lever that rested on a axil. At first we had a trebuchet that's fulcrum was 29cm off the ground, a lever that was 66cm long with an 1 to 8 ratio. We also used 5 rubber bands and a flat head nail holding the clay ball. Are axle was made out of wood and was 7mm thick. The trebuchet fired at about 5 meters We did some testing and figured out what modifications would would make are clay ball fire the farthest we found out that it would be better if we had the fulcrum was 37cm off the ground and the lever was 50cm long with a 1 to 1 ratio. We also decided that it would be better if we added 10 rubber bands because then we would have more power and it would launch farther. We also changed the nail to to a finishing nail so the balls string wouldn't get caught and slow the ball down. The last thing we thing we changed was the axle to a metal axle that was 2cm thick. The reason we did this was because the small wooden axle was about to break when we put all the rubber bands on. Now are trebuchet fires at about 45 meters. When testing we found that a lever with a length of 47.5cm is the best for firing a catapult or trebuchet. We figured out that the lever can't be too long or too short when trying to fire an object the farthest. When doing are experiment we tested a bunch of different sized levers to see which one worked the best. When testing we made sure that all the ratios on the levers where the same, and made sure to keep everything the same except for the levers. That way nothing was changing except for the size of the lever. Having nothing change is how we knew the experiment was correct. When we where testing we took the lengths, and how far the object was launched. We found when the lengths of the levers where long they had trouble getting enough speed to launch the object the farthest. Are two longest levers launched at about 5 meters. The two shortest levers launched at about 11 meters. When we launched the lever that was in the middle we found it worked the best because it launched the farthest. It launched at about 14 meters. Because the one that was 47.5cm launched the farthest it is the best lever. I think the one in the middle launched the farthest because it wasn't too land and two heavy or two small and two light. Because it is so much lighter the lever can move faster than the longer heavier ones. The smaller levers launch the ball to late making it hit the ground earlier because the angle it fries at is pointing at the ground.
Calculations and comparison
Distance horizontal: 45 meters or 147.63 feet D vertical: 13.82 meters or 45.34 feet Time in air: 3.3 seconds V horizontal: 13.64 m/s or 30.5 mph or as fast as a 4 year old greyhound from utah named Blaise V vertical: 16.17 m/s or 36.17 mph or 9 more mph than Usain Bolt V total: 21.15 m/s or 47.31 mph or slightly slower than THE FASTEST DOG IN THE WORLD! A 6 year old greyhound from australia named fanta. K: 137.5 N PE: spring 4.64 J KE: 2.9 J Release angle: 51°
Reflection
On this project I feel like I did a good job staying on tack and not getting that distracted. I also did a good job at having fun and working at the same time. On this project I feel like I could have done a better job at being a group leader and not just doing what I was told to do. I also should have thought things over more before I made changes to the project.