[DonRotolo]

OK, so all this gets me thinkingf: What makes a winning mousetrap car?

Well, if F=ma, and F is fixed, to maximize a we need a small m. Right? So I conclude the way to get the most is to have the smallest mass possible, all else being equal.

Yes, one must ensure the drive system is suitable - the string pulling the axle, the friction between the wheels and the ground, all that needs to be good, but there's a wide range of 'just fine' there. Also, you need to bring friction down to a negligible factor - those bearings are sick, but quite right.

If the CDs used as wheels could be swiss-cheesed, you should be able to get a lot better. Can you cheese the trap, too? (no pun intended).

Don