Question about rotation for physics?

Question

Suppose you are designing a car for a coasting race-- the cars in these races have no engines; they simply coast downhill. do you want large wheels or small wheels? Do you want solid, disk-like wheels or hoop-like wheels? Should the wheels be heavy or light?

Answer 1

Hello gator -

Well in my opinion -

You want large wheels - this reduces the axle speed to a minimum relative to vehicle speed, which reduces the effect of axle friction to a minimum.

You want hoop wheels, for the same reason that you want light wheels. Added weight has no effect on the acceleration of gravity, which is constant regardless of weight. However, lighter weight means reduced normal force which means reduced friction, both at the axles and at the rolling surface.

For the same reason, you want a minimum number of wheels. Four is better than six, three is better than four, two is better than three, etc.

Good luck!