Fire Away

Requirements/Description

For this project, each member of our team had to assemble our own type of catapult/trebuchet that could launch a projectile as far as possible. Our team consisted of Lindsey Oppegard, Sola Takeda, Aidan Baggs, and me. We recorded data for the trebuchet and made the calculations that explained the designs. This project was mostly individual, except for when we needed to ask for advice or clarification. Here were the requirements for the proof of efficacy document:

1. Photos of your trebuchet

2. Written description of your design

3. 5 modifications you made based on class experiments and WHY you made each modification (science reasoning)

4. Your Claim Evidence Analysis Poster Slide explaining your experimental findings

5. Technical Specifications for your machine including:

a. Mass of your projectile

b. Horizontal Distance

c. Time in air

d. Vertical Distance (d = 1/2 a t^2) where t is the time falling.

e. Horizontal velocity (v = d/t)

f. Vertical velocity (v=at)

g. Total velocity (a^2 + b^2 = c^2)

h. Release angle (use protractor or tan x = vvert/vhoriz)

i. Spring constant (k=F/d)

j. Initial Spring Potential Energy (PEspring = 1/2 k x^2)

k. Kinetic energy of the ball (KE = 1/2 m v^2)

l. Percent energy converted (KE/PE)

6. Main selling points of your design

Data Points

Here are the main calculations also seen in the Proof of Efficacy document.

• Mass of Projectile; about 0.08 kg

• Average Horizontal Distance; 7.8 meters

• Time in air; 1.2 seconds

• Average Vertical Distance; 1.9 meters

• Horizontal Velocity; 6.5 m/s

• Vertical Velocity; 5.88 m/s

• Total Velocity; 8.76 m/s

• Release Angle; 120°

• Spring Constant; 166.5 N/m

• Initial Spring Potential Energy; 19.49 J

• Kinetic Energy of the Ball; 0.31 J

• Percent Energy Converted; 1.59%

Reflection

Completing this project during online learning proved to be difficult for me personally since I couldn't really learn from my other classmates' ideas and mistakes. My group was helpful when I had specific questions about the project, but there wasn't that much on this assignment that we could collaborate on.

The two things I did well on this project were time management and perseverance. From the start of this project, I was able to plan the trebuchet out using the materials I knew I had in my home. This made it very easy for me to adjust things when necessary and get ahead early. Next, I was persistent enough to try out several different materials in place of the arm because I was struggling to get the projectile as far as I wanted. I tried using my lacrosse stick, a broom, and a rake, but ended up using a plastic baseball bat. Eventually, I was able to shoot the clay ball 6.3 meters which was past my goal.

Some things I feel I could've improved upon during this project are communication with my group, and staying consistent through to the end. Our group barely turned on our microphones for more than 5 minutes each day. I think the reason for this was that we did not have a presentation or anything we needed to come together on, so we opted to complete the tasks on our own. Also, towards the beginning of this project I was very confident, which ended up negatively affecting me by the end. This is because I thought I had more time than I did, and I didn't realize we had to make certain modifications to the machines. Hopefully in the next project I am able to be more realistic with myself and my abilities.