12th Journal Entry

9-9-10

Today we tested our methods more and identifyed the forces at work in our car. We realized that the car applied to all three of Newton's laws. It applied to newton's first law because it would not move unless moved by our propulsion system and it would not stop until the friction of the axles on the wheel and the air ressitance acted.It applied to the second law, F=ma, because when we took off some mass from the car, it went faster because less force was required. It applied to the third law because when the string is attatched , it pulls on the string with the same force that is put on it, causing it to turn and the springs are pushed just as they push the car. We estimate that finding these connections and changing the car accordingly will help us make the car better by at least 20%, meaning we might hit 6 or 7 meters on the long track because we will know why things worked or not. Our new measurements are Mass: 280g  Top distance travelled: 5.43m Time I:.37 Time F:5.54. This means that the velocity initial is 2.7 because 1 divided by .37 is 2.7, our velovity final is .98 because 5.43 divided by 5.54 is .98. To get these, we used the formula v=d/t. We got the acceleration measurements by using the formula a=vI-vf/t and found the answer to be .31 mps.

~Tanner