Proof of Efficacy of Trebuchet
1. Pictures
2.Goal of the Project
The goal of the project was to build a catapult or trebuchet that could make an object travel as far as possible. Some of the restrictions were that it had to be stationary, reusable, and have a base that sits on the ground, two legs that hold up an axle, and a lever with both a load and effort. It also had to be one meter in all directions and could be carried by one person.
3. Design Features
B. Dimensions:
C. Experiment Conclusion:
If the string is between 35 cm and 40 cm, it is the preferred length for maximum distance. In our experiment we tested seven different lengths of string to see which one would carry a 10 gram ball the farthest. We tested a 20, 25, 30, 35, 40, 45, and 60 cm ball. The 20 cm string length went an average 15 meters and with each new length of string the ball approximately went an additional five meters. It topped out at 35 cm traveling on average 30 meters. At 40 cm the ball’s average was 26 meters. When we went to a 45 cm string the data was inconsistent, sometimes it would go 20 meters other times it would not go any where. We decided to try a 60 cm length string to see if it did the same thing and it did, so we concluded that that data would be invalid. While running the experiment we noticed that the string needs to be long enough to rotate the ball but not to long so it would drag that is why a 35 cm to 40 cm would be best because our project it only 58 cm tall.
3. Calculations:
A. Math
Velocity Total: 24.7 m/s
Velocity horizontal: 11.11m/s
Velocity vertical: 22.05m/s
Time in air: 4.5 seconds
Time up: 2.25 seconds
Time down: 2.25 seconds
Distance total / horizontal: 50 meters
Distance vertical: 24.8 meters
Release angle: 63.26 degrees
Spring constant: 285.7 N/m
Spring potential energy: 78.22 J
Kinetic energy of the ball: 3.1 J
Detailed Calculations:
The goal of the project was to build a catapult or trebuchet that could make an object travel as far as possible. Some of the restrictions were that it had to be stationary, reusable, and have a base that sits on the ground, two legs that hold up an axle, and a lever with both a load and effort. It also had to be one meter in all directions and could be carried by one person.
3. Design Features
- The modifications that we made to our project was:
- Taller legs; we added taller legs so that the arm had a higher release point causing it to go farther.
- A 35 centimeter string; we did this because if the string was too long it dragged on the ground causing it to slow down the flight path, if it was too short it could not flip the ball easily.
- Having a total of four rubber bands, we originally had two but we added more so that he release had more power meaning it could go farther.
- A different axle; we changed our axle because a wooden one was too weak so we changed it out for a gardening rod because it was stronger.
- A blocker; we added a block between the two legs because if we didn’t we would have run the risk of getting hit by the arm after we released it.
B. Dimensions:
- 31.5 cm leg height
- 24.5 cm base length
- 19.5 cm base width
- 63 cm arm length
- 21 cm effort
- 42.5 cm load
C. Experiment Conclusion:
If the string is between 35 cm and 40 cm, it is the preferred length for maximum distance. In our experiment we tested seven different lengths of string to see which one would carry a 10 gram ball the farthest. We tested a 20, 25, 30, 35, 40, 45, and 60 cm ball. The 20 cm string length went an average 15 meters and with each new length of string the ball approximately went an additional five meters. It topped out at 35 cm traveling on average 30 meters. At 40 cm the ball’s average was 26 meters. When we went to a 45 cm string the data was inconsistent, sometimes it would go 20 meters other times it would not go any where. We decided to try a 60 cm length string to see if it did the same thing and it did, so we concluded that that data would be invalid. While running the experiment we noticed that the string needs to be long enough to rotate the ball but not to long so it would drag that is why a 35 cm to 40 cm would be best because our project it only 58 cm tall.
3. Calculations:
A. Math
Velocity Total: 24.7 m/s
Velocity horizontal: 11.11m/s
Velocity vertical: 22.05m/s
Time in air: 4.5 seconds
Time up: 2.25 seconds
Time down: 2.25 seconds
Distance total / horizontal: 50 meters
Distance vertical: 24.8 meters
Release angle: 63.26 degrees
Spring constant: 285.7 N/m
Spring potential energy: 78.22 J
Kinetic energy of the ball: 3.1 J
Detailed Calculations:
B. Conversions to the Imperial System
5. Why You Should Buy Our Trebuchet
You should buy our trebuchet because it is very consistent by going the maximum distance the ball could travel with our trebuchet. Our trebuchet is very lightweight and could be taken anywhere with great ease. It only takes four rubber bands to power our trebuchet which is a good source to power it because it is renewable. For these reasons you should buy our trebuchet.
- Total Velocity: 24.7 m/s is about 55.25 mph
- Horizontal Distance: 50 meters is about 165 feet
- Vertical Distance: 24.8 meters is about 81.5 feet
5. Why You Should Buy Our Trebuchet
You should buy our trebuchet because it is very consistent by going the maximum distance the ball could travel with our trebuchet. Our trebuchet is very lightweight and could be taken anywhere with great ease. It only takes four rubber bands to power our trebuchet which is a good source to power it because it is renewable. For these reasons you should buy our trebuchet.
Here is a video of our trebuchet
Reflection
Throughout this project I learned that communication is very important because when we communicated with one another we worked well together. By setting up a plan for what needs to get done at certain times we were always on task. We also all took responsibility for different parts of the project, so there was not one defined leader, but we all got to practice our leadership skills.
Some things that we needed to take into account while testing was where we while we were holding the arm down to fire it because several times our faces, arms, and feet got in the way of the long arm. Another thing that we needed to work on was making sure the trebuchet was not harming itself because it was so powerful, the arm kept breaking the nail that held the projectile. The arm was also to powerful for the safety guard so it kept breaking.
Some things that we needed to take into account while testing was where we while we were holding the arm down to fire it because several times our faces, arms, and feet got in the way of the long arm. Another thing that we needed to work on was making sure the trebuchet was not harming itself because it was so powerful, the arm kept breaking the nail that held the projectile. The arm was also to powerful for the safety guard so it kept breaking.