In this project, we had to launch an object as far as possible. We had the restrictions of; it must have a base that sits on the ground, two legs that hold up an axle, and a lever arm with both a load and effort end. It must be portable by one person and have no dimension larger than 1 meter. We could not provide anything extra to the firing ourselves, we were only able to get it set and release it. Our design was simple our trebuchet was powered by rubber bands and has an arm at a 2 to 3 ratio. It is all smaller than 1 meter and it met every criteria.
The extra modifications we made are:
For our trebuchet we determined that the optimal nail angle is 10° backwords. For our experiment we tested 6 different angle measurements they were 90°, 15° forwards, 15° backwards, 5° forwards, 5° backwards, and 10° backwards. We had 3 trials for each different angle and then we took the average of how far each went in meters. We found the average of each angle, which were: 11.12m for 90°, 9.5m for 15°forwards, 9.2 m for 15° backwards, 12.2m from 5° forwards, 13.7m from 5° backwards, and 14.4m for 10° backwards. For each test we keep the everything the same expect for the angle of the nail, so the amount of rubber bands and how far down we push the arm were always the same. With this data we found that the 10° backwards had the farthest distance and the projectile was shot. The optimal angle for releasing a projectile is 45°. But because of air resistance the angle is decreased to about 30°, when our projectile is released it released close to 30° relative to the ground. With this we concluded that the optimal nail angle for our trebuchet is about 10° backwards.
We had to gather data on our trebuchet they were:
Distance horizontal: 25 meters
Time in air: 2.09 seconds
Velocity vertical = 10.241 meters per second or 22.91mph
Velocity horizontal = 11.96 meters per second or 26.75mph
Velocity total = 15.74 meters per second or 35.21mph
Kinetic energy of ball = 0.87J
Spring constant = 81.4 newtons per meter
Potential energy of spring = 7.5J
The extra modifications we made are:
- We changed the length of the firing arm. We cut the length of our arm to half its original length and made the ratio 3 to 2. With less weight on the arm to move, it was able to fling the projectile farther.
- We also changed the mass of the projectile. Our original projectile weighed about 15 grams, we cut the weight to 7 grams. We did this because with the bigger mass the projectile wanted to move less, so making is smaller it was able to cut through the air better, with being affected by air resistance less.
- Our third change was changing the length of the string that the projectile was attached to. We changed the length of the string to about 40cm and 20 cm when looped around the projectile. If the string was too long it would make a higher arc making it go a smaller distance but greater height, The 40 cm long string is better because it made a higher and longer arc, lus making it go farther.
- Our fourth change was modifying the number of rubber bands. We originally had 3 rubber bands but we quickly found that it wasn't going far at all. So we changed it to 6 rubber bands. With more rubber bands we were able to have more power when we stopped holding the arm.
- Our fifth modification was changing the length of our rubber bands. We did this because is assisted in increasing how far back we could pull our arm without snapping the rubber bands.. With that we were able to make the distance of the projectile go farther.
For our trebuchet we determined that the optimal nail angle is 10° backwords. For our experiment we tested 6 different angle measurements they were 90°, 15° forwards, 15° backwards, 5° forwards, 5° backwards, and 10° backwards. We had 3 trials for each different angle and then we took the average of how far each went in meters. We found the average of each angle, which were: 11.12m for 90°, 9.5m for 15°forwards, 9.2 m for 15° backwards, 12.2m from 5° forwards, 13.7m from 5° backwards, and 14.4m for 10° backwards. For each test we keep the everything the same expect for the angle of the nail, so the amount of rubber bands and how far down we push the arm were always the same. With this data we found that the 10° backwards had the farthest distance and the projectile was shot. The optimal angle for releasing a projectile is 45°. But because of air resistance the angle is decreased to about 30°, when our projectile is released it released close to 30° relative to the ground. With this we concluded that the optimal nail angle for our trebuchet is about 10° backwards.
We had to gather data on our trebuchet they were:
Distance horizontal: 25 meters
Time in air: 2.09 seconds
Velocity vertical = 10.241 meters per second or 22.91mph
Velocity horizontal = 11.96 meters per second or 26.75mph
Velocity total = 15.74 meters per second or 35.21mph
Kinetic energy of ball = 0.87J
Spring constant = 81.4 newtons per meter
Potential energy of spring = 7.5J
This project was the by far the best one because we were able to pick our groups and have anyone in them. Have your friends in a group makes the work fun and easier to do. But I didn't really work as much ok the project, and I plan to improve on that when working with friends. But cooperating with my group was incredibly easy because I already knew them and what they liked and didn't like.
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