Mousetrap car questions?

I'm building a mousetrap car for my high school physics class. The goal is to get it to go as far as possible, and the materials allowed are: Mouse trap (given to us) String (given to us) Cardboard/wood for base 2 wheels (CD's, records, etc.) 2 dowels Other approved recyclable materials Is it more beneficial to use CD's or records for the wheels? And if records are better for the task, then should I use 7" or 12" ones? Also, how long should the body and arm be in proportion to the wheels?
Answers

Philomel

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.

lee26loo,異域秦後人

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 !!

oldprof

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.