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Our task was to create a trebuchet or catapult that launched a projectile as far as possible. The catapult had to include a swinging lever, base, and axle.
What our car consists of:
Our car was made out of a wood chassis, metal axles, toy car wheels with a cd glued on them because the CDs were less rolling resistance and less friction, Seats for the passengers/pennies , A nail, and a rubber band.
Prototypes of our car: We started with a thick and long piece of wood with very large axles. We soon realized we had no way to attach the rubber band so we then cut out a, piece of the wood in the back where the axle was so we could attach the rubber band. We found some CDs lying around so we attached them to the car. then we strapped the penny down with rubber bands Then started testing. The car would not drive straight it was super slow and super inefficient because of how heavy it was it required many wraps in the rubber band. For our second prototype we completely redesigned it we used a much skinner piece of wood, and small metal axles but this time we used small car wheels that attached to the axles. Then we cut another hole in the body to attach the rubber band to the axle and then used rubber bands to hold the pennies in place this one was faster but never went straight and also broke a lot. For the next prototype, we grabbed a medium-sized piece of wood and drilled holes for the axles to go into we put the small metal axles attached then to the wheels which were glued into the CDs from the prototype so the car was rolling on the CDs. Then we made seats for the pennies because who wants to be strapped to their vehicle? It was working well but not super fast and still not rolling straight so we decided to put star was on the front and back of the car and put the axles in the this made the wheels go straight and much less friction so the rolling speed was higher.
Calculations:
Kinetic Energy: 0.1643J (at 1m)
Total Energy: 1.03J
Thermal Energy: 0.09J (at 1m)
Potental energy: 0.96J (at 1m)
Things that I did well: I think that I did well balancing out the wrok that I did rather than foucing in on one thing. We slip the work load evenly so that we all had something to do. I also think that I did well on making changes and think of ways to make our car and overall project better. I also brought many ideas of things that we could do or ways that we could do them.
Things that I could have done better: I think that I could have done better with helping out more with making the graphs also having more empathy. I also think that I need to work on taking a little les of the lead role and letter other people put more ideas to the table> overall I think that our group did a very good job working together
Our task was to create a trebuchet to launch a projectile. The assignment was to launch the projectile as far as we could we created one which worked, but not as well as we would have liked so we went back to the drawing board to make modifications
Our machine consisted of:
Two legs
A base
An axle
An arm with a screw on bottom to attach rubber bands
A counter weight to increase velocity
A hook in base to attach the rubber bands
Our original design worked, but it didn't go very far our group waas reaching ten meters while some other groups were reaching 40 meters. So we went back to the drawing board and made some modifications.
Arm ratio 1.5 to 1 which caused. weight balance so all energy goes to projectile not the arm.
Number of rubber bands. It is more Pe to Ke
Longer arm. More distance in same time = gain in velocity
Counter weight. PE= mgh more m more PE
Longer and skinny projectile. less air resistance
Lighter arm. Force= mass times accelration.
More pull back distance. More Pe to Ke 1/2 kx squared more Ke
No stopper. Allow PE to convert to KE in follow through
Our trebuchet has been started from the ground up without a sturdy base; everything else will be weak. That's why we picked out a heavy strong sturdy piece of wood. Then we selected two 2x4 legs that would be sturdy and would not move around. We also considered to height we wanted it to be taller to accumulate the long arm. Next we grab a piece of wood for an arm we found the ratio for the arm we also added a counter weight and more holes in the arm to make it lighter.
Calculations:
Projectile mass: 17 g
Horizontal distance 13 meters
Time in air 1.78 seconds
Vertical distance 15.5 meters
Horizontal velocity 8.7 m/s
Vertical Velocity 17.4 m/s
Total velocity 19.4 m/s
Angle of release 64 degrees
Spring constant 50 newtons per meter
initial spring potential energy 6.75N
Kinetic energy of the ball 33.7 KGM/S
percent converted from Pe to Ke 51% conversion
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