The Goal: The goal of this project was to use a trebuchet and launch a projectile as far as possible. The restrictions for this were that the trebuchet couldn’t have a length of more than one meter when the arm was fully extended. The arm also had to be supported by two legs or pillars. As well as having a platform. Our final product essentially remained the same aesthetically. However, there were many fixes and tweaks that were made to it from the beginning until the end. Examples below:
Things that we Changed: Nail Position: It was originally short and head a large head
We changed it to a longer nail because it would cover a larger distance in a shorter amount of time, meaning a higher velocity.
We then found a long nail with a small head which meant that the string of the ball wouldn’t get stuck on the head.
Rubber Bands: Very little were used
We began adding more rubber bands to create more tension
Axle Height: It was initially placed lower in the beginning
We gradually moved it up to find the optimal height for the farthest distance
We finally found that the best height was 10.5” because it would go a longer distance over a shorter amount of time, resulting in a higher velocity.
Hole Width: Originally small and tight
We made the width of the holes that hold the axle bigger to reduce friction.
Allowing the axle to rotate more easily
Weight of Ball: Started off small
We realized that a heavier ball would travel farther because it wouldn’t be affected as much by air resistance.
We also lost a lot of balls, so we took the opportunity when making a new one to make it bigger.
Clear Paragraph: In our project, we found that the optimal axle height for our machine is 10.5” for it to launch the projectile the farthest. Generally speaking, the higher the axle is, the farther a projectile will be launched because it’s a greater distance over the same amount of time, resulting in a higher velocity. In our experiment, we tested four different heights. 8.5”,9.5”,10.5”, and 11.5”. We launched the projectile using rubber bands to provide tension on the arm, slinging it forward when released. For each height, we tested it 3 times to get an average distance that the projectile was slung. We found that the more rubber bands we used to launch the projectile, the farther it would go because it would provide more tension. From that discovery, we began to add more and more to get as much tension on the arm as possible. Our averages typically stayed around the same at 14.3m,14m,19.8m, and 13.7m. To calculate the relevant concepts, we took our best trial with a distance of 23 meters in .85 seconds.
Data Total Distance= 23 meters or 75 feet Time in air= .85 seconds
Horizontal Velocity 27 meters/second or 60 mph
Vertical Velocity 3.5 meters/second or 8 mph
Angle of Release 7.4 degrees
Spring Constant(k) 157.5 Newtons/meter
Potential Energy of Spring 36.2 Joules
Kinetic Energy of ball 2.5 Joules
Vertical Distance 3.5 meters or 11.5 feet
Energy Transferred 7% Reflection: This was a very interesting project to work on. I wouldn't say it was the most fun thing to work on, but I definifinitely learned a lot. I learned a lot about the project we were working on and myself. I don't feel that my group had the best chemistry or worked together the best. We didn't have an equal amount of work for everyone. I learned that some people like to take initiative, and not in the best way, and do everything themselves. I also learned that I actually like to be involved in a project. Although I actually did learn a lot, I wouldn't say I had the most fun doing it.