Fire Away!

Our trebuchet is a design that has a goal to launch a projectile a certain distance. Our trebuchet has an arm that is 24 inches long, legs that are 17 inches each and a base that is 24 x 12 inches. We have about 16-20 rubber bands to add a stronger spring constant. We also have one spring which also increases the spring constant. Then, we have an axle that is 11 inches long. To launch our projectile we have a bolt under the nail that the projectile hangs on that you step on to launch our projectile. The Materials we used are metal and wood.

Selling Points

Some of our main selling points include our spring constant, arm length, bolt to launch projectile and the length our projectile is launched. First, for our first selling point we have a good spring constant of 12.96 joules, this helps us collect enough energy to send the projectile far. Second up is our arm length, Our arm length is longer and lighter than most and it launches a projectile and avg. of 10 meter further than previous prototypes. Next up is our bolt that you step on to launch the projectile, it is very easy to use and it is guaranteed to exert more power down on the arm. Lastly our projectile launches in the range of 30-45 meters each time.

8 Modifications

1-Our first modification is the number of rubber bands used, we modified this because it added a stronger spring constant to our projectile causing it to launch way further.

2- Our second modification is our arm ratio. We added a couple of holes so that you can adjust your arm on the axle to have a bigger or equal load on each side of the arm. 

3-Our third modification is our arm length. We switched it from 18 inches to 24 inches. We did this so that we had a better release angle that launches it further. 

4- Our next modification was our projectile material. We changed the material because it is lighter and causes less air resistance.

5- Our fifth modification is the projectile mass. We changed this so that it would fly through the air and also have little air resistance.

6- Our sixth modification is our nail placement on the board, we changed the nail so it is towards the edge of our board to maximize the spring constant.

7- The next modification was the axle rotation. We made it so it would not rotate and we did that because it provided less friction between the arm and axle.

8- We lastly changed our arm mass to one that is way lighter. We did this because it is quicker to launch the projectile and easier to exert a big force when pulling down the arm.

Content

• Mass of projectile: .006kg, the mass is the total of atoms that are inside of a projectile/ weight of rubber door stopper.

• Horizontal distance: 42m, this is the horizontal length that our projectile was launched.

• Timer in the air: 3.49s, this was the total time our projectile was in the air from when it launched from the trebuchet to when it hit the ground

• Vertical distance: 11.9m, this was the maxim height the projectile was at while launched ( the highest it got)

• Horizontal velocity: 12 m/s, This is the velocity the projectile hit while going horizontal from point a to point b.

• Vertical Velocity: 34.2 m/s, this is the total velocity the projectile hit while going up vertically.

• Total Velocity: 36.24 m/s, this is the total velocity the projectile went going horizontally and vertically together.

• Angle of Release: 70 degrees,  the angle of release for our trebuchet is 70 degrees. This is the angle where the projectile departs away from the arm and launches.

• Spring Constant: 490 n/m, This is the amount of resistance our spring and rubber bands hold against the arm.

• Initial spring potential energy: 12.96 joules, the energy stored in the stretch of an object.

• Kinetic energy of the ball:3.95 joules, the energy due to motion.

• Percent of energy transferred: 8%, this is how much potential and kinetic energy was used.