well you can figure out how far it would travel based off the force Gravity would put on the object as it fell, anything extra would be the Fly wheel.
The acceleration on the object would be:
where a is the acceleration due to gravity the object will feel
g is the acceleration due to gravity in free fall (9.81m/s)
theta is the angle between the surface of the ramp the object is falling down, and the floor.
find the time, t, it takes for it to hit the floor from where it's dropped and you can find the velocity it should have if it was gravity alone:
then if you have the coefficient of friction for what-ever surface your floor is made out of you can find the distance it should travel alone as:
dx = V(t)+.5at^2
where dx is the distance it should travel
V and t are the same from above,
a is the deceleration due to friction which can be found by ((mu)(Fn))/(m)
mu is the coefficient of friction
Fn is the normal force
and m is the mass of the car.
This is just one way to do it, and I'll admit it seems rather long and tedious, your best bet would be to talk to Graham, IIRC he's a physics teacher and would probably know a better way of doing this than me and my Physics I: Intro to Mechanics course.