Final Thoughts

After completing our car, we concluded that it was not as successful as we wanted it to be. It was not able to roll very far using just the force of gravity and even with a push, the car did not roll far. The first version of our car included small wheels in the back with washers attached but the washers caused the rolling to be uneven. Even after switching the back wheels to larger ones, although improving the car's stability and ability to roll, it was still not enough to make our car successful. In the future, we would like to further improve our car by doing more research about how it could be successful. An idea that we already have is to have the axles roll instead of the wheels because when the axles roll, the dowels are smooth so there is less friction as compared to the wheels which have a lot of friction when the cardboard rolls. This friction force was a huge problem as it also wore down our wheels quickly. Another idea is to increase the weight of our car because when the mass is bigger, then the force of gravity will be larger and the force will be strong enough to push our car down successfully but this will only have a chance of working if the friction force can be minimize and if we can stabilize our wheels.

Final Thoughts

Overall our car was not successful to the degree of completing the entire course solely with the force of gravity and did not travel as far as anticipated.

The highlights of our car, however, were a fully functional steering and braking system along with a frame that was able to support the weight of the driver.

In the future if we were to modify our car we make some engineering changes in our car. The biggest change that would effect our car’s performance would be increase the size of the back wheel compared to the front wheels. This increases would result in an increase in the magnitude of the force of gravity and decrease the magnitude of friction. As the radius of the back wheel increases the angle theta increases. When theta increases the magnitude of gravity (mg sin theta) increases and decreases the magnitude of friction (cmg cos theta, c= coefficient of rolling friction).