Overview
In this project my group and I had to make an alternate energy car. The first thing we did to start this project was to brainstorm ideas. Then once we decided on making a rubber band car, we started building. We decided to use a longer piece of wood for the body of our car so the rubber band could stretch more giving the car more potential energy to start with. Then for the wheels we used a pipe that we had cut out with cardboard in the middle so it fit our axle. Also for the wheels we hot glued a rubber band to each of the back two wheels. To get the car moving all by its self we hammered a nail underneath and closer to the front of our car to hold the rubber band. Then someone would wind the back axle up with the rubber taped down in it. Then, after you wind it you let go and the car would start moving.
Calculations and Graphs
Velocity
When my group and I had to find the velocity of our car we split up the velocity into three parts. The velocity for the first meter. The velocity for the second meter. Then the velocity for the last seventy centimes. To find the velocity of our car we used distance over time.The velocity for the first meter for our car was .83 m/s or 1.86mph.Then velocity for the second meter was slower than the initial velocity because it is starting to slow down. So the velocity would be a bit slower. So the velocity for our second meter was .79m/s or 1.77mph.The last 70cm our car traveled the velocity decreases because most of the speed has been lost because the rubber band is fully unwound. So our final velocity was .58m/s or 1.3mph.
When my group and I had to find the velocity of our car we split up the velocity into three parts. The velocity for the first meter. The velocity for the second meter. Then the velocity for the last seventy centimes. To find the velocity of our car we used distance over time.The velocity for the first meter for our car was .83 m/s or 1.86mph.Then velocity for the second meter was slower than the initial velocity because it is starting to slow down. So the velocity would be a bit slower. So the velocity for our second meter was .79m/s or 1.77mph.The last 70cm our car traveled the velocity decreases because most of the speed has been lost because the rubber band is fully unwound. So our final velocity was .58m/s or 1.3mph.
Energy
My group and I had to find the different types of energy. We started with finding the spring potential energy since a rubber band is a spring. The Spring Potential energy was 2.95 Joules. Then we moved onto finding the Kinetic Energy of our car.The amount of Kinetic energy during the first meter was .28 joules.The amount of kinetic energy in the second meter is .25 joules which is less than the first meter because there is less potential energy left. For the last 70 centimeters the kinetic energy was.13 joules which is a lot less because most of the potential energy is gone and most of that energy converted to thermal.Which leads us into our third type of energy thermal.For the first meter our thermal energy was 1.27 joules. For the second meter the thermal energy was 2.3 joules. Then at the end all of the energy was thermal because the car was not moving. As you can see most of the potential energy in our car was converted into thermal energy.
My group and I had to find the different types of energy. We started with finding the spring potential energy since a rubber band is a spring. The Spring Potential energy was 2.95 Joules. Then we moved onto finding the Kinetic Energy of our car.The amount of Kinetic energy during the first meter was .28 joules.The amount of kinetic energy in the second meter is .25 joules which is less than the first meter because there is less potential energy left. For the last 70 centimeters the kinetic energy was.13 joules which is a lot less because most of the potential energy is gone and most of that energy converted to thermal.Which leads us into our third type of energy thermal.For the first meter our thermal energy was 1.27 joules. For the second meter the thermal energy was 2.3 joules. Then at the end all of the energy was thermal because the car was not moving. As you can see most of the potential energy in our car was converted into thermal energy.
The time and distance graph shows that for the first two and a half seconds the car is moving close to the same speed. But when the car goes past two meters it starts to slow down and not cover ground at the rate of time before it.
Friction
The rubber bands on the back two wheels provide a grippy tire that you do not need to replace. The front two wheels of the car have no rubber bands so the wheels can move fast and freely because the axle does not have a rubber band pulling on the axis. Some problems that we have had with friction is that since our axel is wood and the blocks holding our axle is wood. Wood on wood was probably not the best idea because molecularly wood on wood isn’t the smoothest material choice.So a lot of the energy is converted into thermal while the axle is spinning instead of converting to kinetic energy. But one of the benefits of our axle is that our pieces of wood holding the axles are thin which means less surface area the axle has to hit while spinning.
The rubber bands on the back two wheels provide a grippy tire that you do not need to replace. The front two wheels of the car have no rubber bands so the wheels can move fast and freely because the axle does not have a rubber band pulling on the axis. Some problems that we have had with friction is that since our axel is wood and the blocks holding our axle is wood. Wood on wood was probably not the best idea because molecularly wood on wood isn’t the smoothest material choice.So a lot of the energy is converted into thermal while the axle is spinning instead of converting to kinetic energy. But one of the benefits of our axle is that our pieces of wood holding the axles are thin which means less surface area the axle has to hit while spinning.
Reflection
During this project I did most of the calculations for the group. I also had to take a bit of a leadership role during this project which was new and suprising to me. During this project my group and I had very good collaboration. We even agreed with each other a little too much which was probably not too good for our project. But my team and I always did our best on the project. We were very efficient with our time. That’s why we were one of the few groups ready to present on Friday. Even though there were some roadblocks, like our car not being able to go the five meters. We worked through it and still got an A on the project. Also this project changed me a bit because it brought out the leader inside me when I was used to being led. Overall I️ really enjoyed this project.