Mousetrap car questions?
Your car will work best with 12" records. with each turn of the record the car will move 6.28* 6 inches = 37.68". If the dowel rotates 10 turns that is 376.80" or 31.4 feet. You could lengthen the mouse trap arm by using coat hanger wire. Go to a drapery Shop and ask for drapery hangers. They use stiffer, stronger wire.
USING ONE INCH LIGHT WEIGHT TYPE BEARING IS THE BEST WAY, SEARCHING EBAY AND AMAZON TO GET THIS PARTS. ** NO NEW IDEA FROM THOSE SO CALLED PHYSIC PROJECT ! REPEAT THE SAME TOPIC FOR YEARS FROM THOSE LAZY TEACHERS !!
You want the car to be as light as possible so that the motive force F from the trap's spring is pushing a small mass m as in A = F/m for the acceleration of the car. The idea is to get to the highest speed U = sqrt(2AS) possible while the force is applied by the mousetrap over the distance S. That will get you the highest possible initial kinetic energy KE = 1/2 mU^2 = mAS and that's what you want. Your car will coast along as long as it has kinetic energy. So you want to start it with as much of that KE as possible. Thus your wheels (and the car itself) should be as light (low mass) as possible for the acceleration and initial speed to be the highest possible. And the wheels should have a high rolling coefficient of friction on whatever race track the car will be running over because you don't want to be spinning your wheels while the trap is yanking on the string. You should probably test your car with both the CDs and the vinyl. One experiment is worth a hundred hypotheses.