This project was called the mouse trap car challenge for a reason. the entire thing proved to be much more difficult than we had all expected. Even when my partner Rashad and I were able to complete the requirement of covering 5 meters, we found it incredibly difficult to improve upon our time of 5.51 seconds. By using the formula v=d/t we found that the car traveled at a speed of 0.907 m/s. All the factors that determined whether or not the car succeed or failed could be explained by physics concepts we had studied.
Newtons first law states that an object in motion will stay in motion, and an object at rest will stay at rest unless acted upon by an outside force. It was crucial that we understood this concept if the car was to succeed. In order to take our non moving car at rest, to an object in motion, we would need to apply an external force. In our case the force we used was created by our lever arm. However, once we got the car rolling we faced another challenge that was much more difficult to over come. Friction. Friction was the enemy say for two places on the car, the contact that our powered wheels had with the ground, and the contact of the string to the axle, In every other place friction was not wanted. We did not want friction because that would mean that there was an external force acting on our car and that meant that it could not continue in its motion.
Newtons second law says that acceleration equals force over mass a =f/m. and in this example, acceleration is very important because we are trying to move the car a certain distance in as little time as possible. Because we had the one mouse trap that was providing our force, the thing that we could change was the mass of our car. If the mass was to great, then the car would have trouble accelerating. this was the problem we originally ran into. our car was to larger and we were unable to accelerate it quick enough.
Newtons Third law states that for every action there is an equal and opposite reaction.
For this project we had the action and reaction pair of the car pushing the ground and the ground pushing the car. This is how the car was able to move in a direction. When the car exerted a force on the the axle and wheels, the wheels began to push against the ground. The ground then pushed back on the wheels with a force that was both equal and opposite. This caused the car to accelerate in the desired direction.
Many factors played roles in whether or not the car was successful. Such as the friction between the wheels and the ground and the fiction between the axle and the car. In the case of the wheels and the ground, our original plan did not work well because we had very smooth wheels that did not generate enough friction. we changed this by adding rubber tape to the new wheels. this increased the friction and helped our car accelerate better.
The other area where we had a friction problem was with our axle and the car. However in this case we had to much friction. This caused the wheels to not be able to spin freely and this reduced our speed and coasting ability. while we were able to reduce the friction in our front axle, we were not able to reduce it in our back nearly as much.
Another area of difficulty for us was the lever arm. We originally thought that having a longer lever arm would be beneficial for us. We were mistaken as the shorter lever arm pulled the same amount of string in a shorter amount of time and was therefore a better tool for powering our car.
Looking back on the project now, I wish that we had had a more solid plan that we could have implemented. We more or less winged it. I also wish that we had started smaller and with a more basic plan, and then expanded. What we did was nearly opposite to that. With all that said, this was actually a very fun project. I enjoyed being able to build and tinker all while applying the physics concepts and knowledge.
And to our car, Thank you, you may not have been the best looking, nor the fastest, but by golly, you got the job done. And for that, I thank you.
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