Physics Lab report

Pinewood Derby Car project

Introduction:

The task was to create our own pinewood car, which had to have a braking system, acceleration and crumple zone. After each one of us created it, we had to launch it from the ramp, which had a trigger point that affected our braking system and activated it. And after activation, the car had to slow down and don’t crack the egg, that was at the end of the ramp. So, I made 3 various models/versions of the car that would accelerate at the start, brake in the middle when the car hits the trigger point and wouldn’t crash the egg at the end because of crumple zone. I chose my 3rd version of the car because I thought it was the most successful one. When I was deciding how to create an acceleration, I remembered force causes acceleration and to increase the force you need more mass, so I added 2 weights on the front of the car so it accelerates. Then, to mitigate the collapse, I added soft things on the front such as paper and cut straws.

There where 3 mechanisms that were employed on the pinewood car. For acceleration, as I already said, I used 2 weights that were attached to the car by small rope. Then, there are 2 straws pasted on both left and right sides of the car, so that when they hit the trigger point, they slow the car down. Also, the 2 weights help the car to stop. By hitting the trigger point, they fell down and slide after the car because they are attached to it by a small rope. Finally, the crumple zone. I cut straws and put them on the front of the car and, also pasted paper on it, so It doesn’t crack the egg. It took about 4 seconds for my car to go down and about a minute to do the measurements.

Results:

The mass of my pinewood car was 207 grams. It took the car 1.9 seconds to complete the first half of the ramp, and 1.7 seconds to complete the second one. The reason for that is because the distance from the launch point to the trigger point was longer than the distance from the trigger point to the end of the ramp. My project was pretty successful. Pinewood car reached the end of the ramp and didn’t crack the egg because the braking system worked, that I have designed. I have also calculated post-race data. Its information is down below in the table:

As I already said, the car took longer to get down the 1st half of the ramp. Momentum at the first half was bigger than the momentum on the 2nd half, because the velocity on the 1st one is bigger than the 2nd one. I calculated it by dividing distance over time. As it was expected my car accelerated at first and then slowed down after the trigger point because of my right use of braking system and acceleration system. But one thing I didn’t expect to happen is that the car actually didn’t crack the egg. I wasn’t 100% sure if it will successfully reach the end without cracking the egg. However, it turned out that it didn’t!

Discussion:

I successfully met all 3 criteria points for the project. The car accelerated, then used braking system and crumple zone worked as well so it didn’t crack the egg. So, for acceleration I used my 2 weights that were in the front of the car which caused pinewood car to increase its speed. Then the braking system I used was, as I have mentioned earlier, a straw and 2 weights. When straw touched the trigger point car stopped a bit. Also, weights were decreasing its speed after trigger point because they fell (created friction and also decreased force). And finally, crumple zone. For that I used some materials that I put on the front of the car so that the collapse with the egg would be weak. And it worked!

Obviously, there were multiple sources of error. One reason that it is impossible to make exact measurements is that the measurement is not always clearly defined. For example, if two different people measure the length of the same rope, they would probably get different results because each person may stretch the rope with a different tension. The best way to minimize definition errors is to carefully consider and specify the conditions that could affect the measurement.

Conclusion:

The pinewood car project was about a personally customized car that had to go down the ramp where it had to accelerate at the start, brake in the middle of the ramp and successfully reach the end where the egg was located, where without cracking it, the car had to touch it. That means it had to have a good crumple zone. My car successfully completed all those challenges and reached the end without cracking the egg, however touching it. Because it successfully met all objectives that I have mentioned above.

Reflection of other projects:

I was actually impressed by how creative were others. They had lots of different and interesting designs, even though some of them were pretty identical, I still enjoyed everybody's designs. I think my classmate Akira's design impressed me the most because I found it absorbing and creative. It also reminded me my design because we had the same idea for the braking system, but we expressed it on the car in different ways. I also posted some questions to Akira and Celine, my classmates.