Fire Away!
For this project we were told to create a catapult that was supposed to send a projectile as far as possible. Our projectile could be anything we wanted it to be as long as it reached the farthest destination possible. We were given three weeks to work on this project in groups of three. We were allowed to use any materials for our trebuchet such as rubber bands, wood, string, clay, etc.
Thought process:
Throughout our process we had learned the perfect amount of rubber bands to use, to get our clay ball (projectile) to go as fast as possible. We also learned how much the wood could sustain with a certain amount of nails. The project helped us see what type of wood would be best used for a trebuchet model. We also learned what type of projectile would be best to use, and what would be the best size for the projectile. Throughout the project we realized where we could best put the nails on the wood ensuring it would go as far as possible without having the nails damage the wood or hit one another. We have a blueprint showing what we thought versus what we changed. Lastly we also had multiple tests showing how far the nails what, how much rubber bands we used, and our new changes.
Blue Print
This blue print shows how our we thought our project was going to look like at the beginning and how it ended up looking overall.
Our clear Analysis poster
From our clear analysis poster we found that with six rubber bands our projectile went farther than with two or four rubber bands. We also found that with a stretched rubber band we can store more potential energy. Then the potential energy transfers to kinetic energy when we pull our arm to let the projectile go.
Calculations
Mass of projectile- Our mass of projectile is 013kg we found this by seeing how much our clay ball weighed on a weight scale set to kilograms
Horizontal distance- Our horizontal distance is 30m, and we found this by seeing how many meters the projectile flew when we pulled the arm of our trebuchet down and let it go.
Time in air- Our time in air is 1.90s, and we found this by timing how long it took the projectile to go to 30 meters.
Vertical distance- is acceleration due to gravity times time squared divided by 0.5, which in our calculations you get 17.7m.
Horizontal velocity - Our horizontal velocity is 15.79m/s and we found this by dividing the distance by time, which for us was 30m/1.90s.
Vertical velocity - Our vertical velocity is 9.3m/s, and we found this by multiplying our acceleration due to gravity by our time.
Total velocity- Our total velocity is 18.3m/s, and we found this by using the phyagroem theorem which is a squared plus b squared equals c squared.
Release angle- for this we had to use tanx equals vertical velocity and horizontal velocity, which was 30 degrees.
Spring constant- for the spring constant we had to divide our force by our distance, and this got us 350N/m.
Initial spring potential energy-to find the potential energy of the spring we had to ½ by our spring constant and multiply that by x squared. Putting our data in for this we got 37.03J.
Kinetic energy of the ball-for this we had to put both the mass and the velocity into the equation, and squaring the velocity by two and multiplying the whole answer by ½. This got us 2.2J.
Percent of energy converted- for this we had to divide our kinetic and potential energy and convert it into a percentage. This got us six percent.
Reflection:
Throughout this project I learned how to communicate better with my group. Although we had some struggles on who was going to do what, and how we were all going to contribute we ended up accomplishing the final project. We had collaborated well to finish this project, working on it and adding additional pieces to make it as good as possible. Even though my group had a little trouble and our trebuchet ended up breaking we still managed to work together and use our creativity and critical thinking to fix it as much as we could. I had learned to use my emotions better with my teammates and made sure I was helping as much as I could, doing whatever we needed without my group having to tell me.
This project helped me learn more about velocity, acceleration, how kinetic and potential energy could be used in everyday activities. This project also helped me learn more about energy overall and how different components have energy in many ways. I am glad I worked with my group on this project getting the best result we could hope for. This project helped me learn how it was to work with different people and how to become friends with them and hopefully work on projects with them in the future.
