Proof of Efficiency of Trebuchet
Dimensions:
Base: 31 by 9 by 4 cm
Two legs: 34 by 9 by 4 cm
Long arm: 67.5 by 4 by 4 cm
Pipe: 39 by 3 cm
3 nails with large heads
6 sets of rubber bands
We had to build a catapult machine that fired a clay ball far. The machine should stay in one place and be reusable regardless of how many times you use it. It has a base that sits on the ground, two legs that hold up an axle, and a lever arm with both a load and an effort end. It is easily portable and is smaller than 1 meter.
8 modifications
- 10 gram ball
2. 10 Centimeter String
We used a 10 centimeter string because if you have a long string the ball will be flying at a lowing angle and if you have a shorter string it will be flying at a higher angle.
3. Strong Base and Legs
If you use a base that is wobbly the machine will just fall and break when firing but if you have a strong base and legs the machine won’t break and will fly.
4. 6 Sets of Tied Rubber Bands
Our class found out that using 3 sets of ties rubber bands were there the best but for our machine that was not tight enough. We used 6 so it would use more force.
5. Smaller hole
We made a smaller hole in the wood for our pipe so it doesn’t just move around. We made a tight hole so when it fired the pipe didn’t move side to side but just up and down.
6. Pipe in the Middle of the Arm
We moved our hole in the wood closer to the middle for our pipe to go into to. We did it to test if it made a difference and it did. Our went 5 meters when it wasn't closer and when it was the ball went 8 meters.
7. Arm Stopper
We made a arm stopper so when the arm hit the wood it would stop and the ball would keep going so the ball flew off and the arm would stop.
8. Nail on the End
We put a nail on the end of the arm so we could put the string onto it. When we did that the ball did not go as far because the clay had to go through the string.
Clear Paragraph
6 large rubber bands on a nail launch the ball from the trebuchet only when the arms are stable. We were building a catapult. My group was testing leg stability. From our data we gathered that if you do not have stable legs your catapult will fall over and the ball would go nowhere. If the arms are stable the ball went forward. Our first test the ball went 5 meters. Our second test went 8 meters. Our third test went 3 meters. If the arms are not stable it will not go anywhere. All of our tests went 0 meters.
Technical Specifications
The mass of the ball is 10 grams. We decided on 10 g because before it was too big and didn’t work. The horizontal distance is 8 meters. The time in air is 1.2 seconds. The vertical distance is 0.7225 meters. The horizontal velocity is 4.7 m/s. The vertical velocity is 8.33 m/s. The total velocity is 90.98 m/s. The spring constant is 92.25 J. The Initial Spring Potential Energy is 2,127.51 N/m. The kinetic energy of the ball is 827,736.04J.
Buy this machine because it goes some ways, it won’t break, and it’s a really cool machine to play with.
Reflection
I build the entire trebuchet while my group messed around. The thing I did very well was work ethic and leadership. One thing I didn't do to well was including my group in the project. I would ask them to help but wouldn't tell them to do anything so they would leave and go talk to a different group. But this project was actually pretty fun because we got to build a catapult. Our catapult didn't fire to far and didn't work to well but it was fun to build it and make calculations and adjust stuff to make it go further.