Do it better
This project was short, only six days of class time, but wee don't need that much because this
project was basically a chance to make something we had done before better.
Most people chose major projects, but my group chose something we did very
briefly, catapults. When the incoming freshmen can to check out San Marin, they
came into our class and we made catapults. Mine was not very professional, so I
decided to make a new one, only this time it was going to be a ballista.
In this project we used knowledge of projectile motion, as well as knowledge of impulse and momentum.
Projectile motion: During our 2nd project, physics of sports, we learned that projectiles go the farthest when launched at a 45° angle. We used this knowledge to get to get Maximum distance.
Impulse = momentum: By lengthening the amount of time the catapult was contacting the ball we increased the impulse which then increased the momentum, making it go further. We increased the length of the arms to increase the impulse.
Spring constant: We twisted rope around to create a rotational spring, and go keep the ball straight both springs had to be close to equal, so I tested each ones spring constant.
Mechanical advantage: MA is the name for the effect of simple machines, like levers. I used levers made of steel pipes to put immense tension the ropes.
Projectile motion: During our 2nd project, physics of sports, we learned that projectiles go the farthest when launched at a 45° angle. We used this knowledge to get to get Maximum distance.
Impulse = momentum: By lengthening the amount of time the catapult was contacting the ball we increased the impulse which then increased the momentum, making it go further. We increased the length of the arms to increase the impulse.
Spring constant: We twisted rope around to create a rotational spring, and go keep the ball straight both springs had to be close to equal, so I tested each ones spring constant.
Mechanical advantage: MA is the name for the effect of simple machines, like levers. I used levers made of steel pipes to put immense tension the ropes.
Reflection
This project was a fail. The ball barely made it off the end. We had grand plans to make a ballista 1/2 the size of an original Roman ballista, but they were too grand to be accomplished in only a few days. We also managed to make a really impressive looking device. It just doesn't work. We were diligent and put tons of work I alone put over 20 hours of work into it. But it just wasn't doable with our time, resources, and restrictions. I have learned my lesson and will stick to traditional catapults, because of the difficulties, inaccuracies, inefficiency, and restraints of a ballista.