After we thought our first car was done and we tested it out, we realized we were going to have to do a lot more experimenting in order to get it to work. Our first car didn't move at all, so we decided to change a lot of things. This experiment taught us that the body of our car was probably too heavy and that was part of why it wasn't moving. We realized that our wheels needed more mobility for the car to be successful. We added straws over our wooden skewers to let the wheels move around something. We also cut down the body of our car, a cardboard box, to make it lighter. The body of the car then became a flat piece of cardboard.
Our finished car:
Standard 2: Quantitative Analysis
We used the forced probe and the theory of gravity in order to determine the mass of our car. Our results from the force probe are shown in the picture below. We used the force to discover the mass by putting it into Fg=mg. From this we got that the mass of our car was .0028 kg which we converted into 2.8 grams. 
We then used video physics and graphical analysis to find the acceleration of our car on a flat surface. Our graph looked like this: 
We determined our acceleration to be 7.188 m/s squared as that was the slope of our line. We could use the slope to find acceleration because it measured the change in velocity over the change in time, which is acceleration. From there, we calculated the net force on our car using Fnet= mass times acceleration. Our equation was Fnet= (2.8g) (7.188m/s2), so we found our net force to be .0201 Newtons.
Standard 3: Qualitative Analysis
Conservation of energy says that energy can't be created or destroyed, and it only changes for,. Tjis explains the movement of our car from the bottom of the hill to the top because our car has elastic potential energy or Us from the balloon at the bottom. As the air is released from the balloon, the energy is changed into kinetic energy, and the car makes it to the top of the hill. Once the car makes it to the top of the hill, some of the energy changes into gravitational potential energy or Ug as the car is at a height, yet it also still has some kinetic energy as it keeps moving. The car only has kinetic energy as it goes down the hill, and once it stops moving it changes back into potential energy. The energy of our car was never destroyed as it only changed forms.
Conservation of momentum says that the momentum before the collison is equal to the momentum after the collison because the total momentum is constant. The combined momentum of our car and our oppoenent's car was the same after the collison as before it. The momentum stayed constant. In other words, the momentum gained by one car was equal to the momentum lost by the other car, which caused the total momentum of both objects to stay constant.
