Race Car Gravity Powered

a.) The race car may not be constructed or treated in such a way that the track's starting mechanism imparts momentum to the car.
b.) Cars with sticky substances on the front of the car and protrusions which may catch on the starting pin/gate shall be disqualified.
c.) The car shall not run on any type of springs.
d.) The car must be freewheeling with no starting devices.
e.) No external sources of power, magnets, engines, jets, compressed air or propulsion systems other than gravity may be used.
f.) If the track's electronic finish line sensor's result is challenged by the Finish Line Judges, the race will be re-staged and re-run.