Alternate Energy Vehicle
In this project, groups from the Fire Away! project were challenged to further their knowledge of design, engineering, and application of physics. In this project, teams were asked to build a vehicle that uses an alternative source of energy to travel a distance of exactly five meters (or as close to five meters as possible) while carrying two "passengers" (rolls of 50 pennies). Groups were not allowed to use any chemical reactions as part of their vehicle and energy source.
To the left is our alternative energy vehicle. My group decided to replicate the mechanics of a wind-up car. To do this, we used a rubber band and wound it around an axle connected to the wheels. When the car is pulled back or wound, it would wrap the rubber band around the axle, which would, upon release, spin the wheels and move the vehicle. This is shown at right.
We decided to place the pennies in the front of the vehicle to add mass and hopefully create momentum as the car began to move. This definitely helped our car travel farther.
Here are some specifications of our vehicle and its performance:
- Distance: 3.25 m
- Mass: 90.16 g = 0.9016 kg
- Total Time: 4 s
- Spring Potential Energy: 1.728 J
- Kinetic Energy: 0.29 J
- Thermal Energy: 0.8075 J
- Rotational Inertia: 0.000072 kgm^2
One modification we made to our vehicle during the course of this project was the addition of hot glue to our back wheels. We did this to add friction as the axle rotated. Before we did this, we found that the back wheels would often spin out against the ground and travel about a foot before stopping. When we added the glue, our wheels were able to grip the ground and travel much farther. This is one way we increased distance traveled by our vehicle.
Graphs of our data, photos, key features, physics explanations, and cost/materials can be found in our slideshow above.
I think that this project was valuable because, during it's course, I learned new equations and how to apply them. I learned about rotational inertia and centrifugal and centripetal forces. I think that my productivity was improved in parts of this project, and my understanding of the physics behind our work was deepened. Though when I wasn't on task, I had a hard time returning to a productive mindspace. Overall, I think my productivity improved between this project and the last.
Here are the links to my teammate's websites: