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My group members Tristen G. and Joslyn W. and I were tasked with the challenge to build some form of a catapult. Like a trebuchet, ballista, mangonel, etc. We chose to build a trebuchet catapult. Our catapult had to be 30x30x30 (cm). Along with the task of creating a catapult, we were tasked to accurately launch a ping pong ball at three circular targets, at three different distances, 2m, 4m, and 7m. Our catapult had to be self firing which meant we had to use a trigger.

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For our trebuchet catapult, we needed a sling to launch the projectile. The length of the sling is supposed to be the same length of the arm doing the launching. The trebuchet uses a counterweight in order to launch the projectile. After testing we realized we needed a trigger for our catapult. Our designs were not fit for a trigger, so getting one installed was a bit of a challenge. Our catapult also seemed to only want to release at one specific moment; thus our ball only traveled 4 meters every launch.

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Here are the calculations involved in our project. In the order of horizontal distance traveled, air time, horizontal velocity, time to reach apex, initial vertical velocity, total initial velocity, launch angle, and the recoil velocity of the catapult.

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We decided to use wood to create our catapult because it'd be sturdy and reliable. We also used yarn, string, and rubber bands for strong pulleys and tension.

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Here is the final device. Our take on a trebuchet catapult. We made sure we had key elements in our catapult, like the sling and pouch, counterweight, and a trigger. We made sure to have just enough counterweight to launch the ball but not so much to over power the catapult.

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Our catapult was not capable of launch the ball 2m. Instead we were allowed to launch ours at the 4m and 7m targets. Our catapult only hit the 4m target for 10 points once out of the four attempts. Although we were finally able to launch our ball over 4m, we missed the 7m target all four times. I think that to better our catapult we should have spent more time developing a trigger. Ours was done too fast to really test. Also our trigger's band snapped during the last launch and we were unable to launch. Even though our device was very accurate and did launch, I would hope to find a way to make it launch at different distances rather than primarily one.