# Remote controlled cars

I was originally hoping to do an experiment with a remote control car, where I would drive it on different surfaces (e.g. asphalt, ice, sand etc.) and calculate the friction between the tyres and the surface.

How would I be able to do this without including the friction of the engine, wheels etc. and keep the variables constant? Is there any other experiment that I could do to make a comparison with that set of data (for example calculate the coefficient of friction between the surface and the tyres and see how this compares to the time it takes to travel a certain distance)?

It seems that you are basically looking to investigate the friction between various road type surfaces.
If you want to look at the problem without friction of the engine why not try the following:
(a) run the car onto the surface in an unpowered state and measure the distance it takes to stop (for a given initial velocity). Remember that the kinetic energy before braking is equal to the work done against the frictional force (apparently the coefficient of friction between cars tyres and asphalt is 0.72, car tyres and ice 0.15, car tyres and cement 0.9, car tyres and wet asphalt 0.45-0.70) and that between car tyres and grass 0.35).
(b) run the car down a ramp onto the surface (again unpowered) and measure as before. Use a light gate to find the speed of the car just before the braking process begins
(c) take a tyre off the car and roll it across the surface (keep it upright)
(d) take a tyre off the car and slide it across the surface
(e) try loading the car with different masses to see what effects this has.

There is a lot about the Physics of car accidents on the internet. The authorities are especially interested in this in the USA and Canada.

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