When we had created a working car, we started testing trials. For our final product, we found that the total mass (including the 200 gram weights) was 750 grams. When we timed it, we had three different times, since our car was only able to go 3.5 meters (but it did go all 5 a few times). The way we found these was by timing the time from (for example) .5 meters to 1.5 meters to get the time for 1 meter. Our times came out as: 0.59 seconds, 0.62 seconds, and 0.68 seconds. We were then able to find the velocitys for each, using the equation V=d/t. These came out as: meter 1: 1,69 meters per second, meter 2: 1.61 meters per second, and meter 3: 1.47 meters per second. Since we used rubber bands, we had to find the spring constant for them. We used the equation F=kd or k=F/d. To find this, we had to use a scale to find how much force it takes to completely stretch the rubber bands, and how far that distance is. We came out with a spring constant of 45.5 Newton meters, which is how much force it takes to stretch the rubber bands and how far it is. Using this, we could find the spring potential energy. Using PE=1/2kx^2, we found that the potential energy was about 2.05 Joules, which is how much energy is in the rubber bands before it is let go of. We also were able to find the kinetic energy that our car had for each meter. Using KE=1/2mv^2, we came up with: 1.1 Joules, 1 Joule, and .84 Joules. Kinectic energy is how much energy is in the car during each meter.