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Re: Friction and area.





Somebody else mentioned the large tires on race cars. Isn't this at
least partly to reduce frictional heating and also due to acceleration
considerations (same torque, larger radius => more acceleration)?


The tires on race cars have a smaller diameter than they used to.

Torque = Force x radius = mass x acceleration x radius

Acceleration = Torque / (mass x radius).

For a given torque, a DECREASED radius results in greater acceleration.
The widest tires are on dragsters where slippage means lost power. A
dragster's designer tries to maximize the sticking friction of the tire to
the dragstrip. One way is to apply benzene or some other solvent to the
tire just before the run, another is to run the tire at low pressure so it
will absorb the high peak torques (thus keeping the tire from breaking
loose), and another is to make the tire wider.

Charlie