We used 2 ‘2x4s and screwed them together for the base of our trebuche. Then we used 2 more 2x4s and measured 14”from one end of the base, and halfway in the middle of each board and screwed that in for the vertical axel holder. Then we drilled a hole in each axel holder with a diameter of 4”. We used a pvc pipe and put it through the holes and drilled a hole in the launching piece of wood. We used a nail to hold the rubber bands we used. We used 3 groups of 2 bands tied together.
Our 8 customizations were:
Strong base- Where the base uses multiple screws to make it solid
Non Moving Base- A base where it’s not affected by the release of the projectile
Weight of Ball- Our weight was 10 g
The number of rubber bands- 6 total , with 3 sets of 2 bands tied together
Length of the Projectile- Our length was 8”
Spacers- We put a spacer around the launching leg
No stopper- We tried a stopper, but it didn’t work for our trebuche
Finishing nail at 60*- We angled the nail the ball string hangs on to 60*
Based on our conclusions, our claim is uncertain. Our original claim was that the closer the rubber bands are to the axle, the greater the force will be, but we re looked at our data and realied that our data is so close together, we can’t make a claim. We figured this out by putting 3 rubber bands 10, 12, 14, and -5 cm from the axle. The -5 is 5 cm on the other side of the axle. From 10 cm away from the axle our average distance the projectile is flung, is 19m. Then from 12 cm away our average was 19 m. Our average distance from 14 cm away was 15 m. Finally our average distance from -5 cm away was 17 m. What we thought this data meant was that 10 cm and 12 cm away was the best. The reason we made our claim uncertain was because we always had one outlier and we were getting the same numbers for each distance so it was too close to make a decision.
Horizonal Distance-25m
Time in the Air- 2.5 seconds
Vertical Distance- 30m
Velocity Horiozontal- 10m/s
Velocity Vertical- 12.25 m/s
Total Velocity- 15.81 m/s
Spring Constant- .00392 N/m
PE Spring- 3.61 J
KE ball-1.24 J
Percent of energy converted- .035%
Angle of Release- 45*-50*