|MadSci Network: Physics|
Frictional force is a function of the applied force moving the object and the coefficient of friction. Coefficient of friction is a function of surfaces in contact and the area of that contact. A greater area of contact gives a greater coefficient of friction. Another factor affecting the amount of friction is impulse. A great force applied in a short amount of time can facillitate a large frictional force while a small force would not generate as much kinetic friction. Also, consider that those tires get pretty hot during a race. If the tires are larger then the heat can be absorbed in greater amount without overheat the tire. Friction is also a function of temperature for some materials like rubber. Hot tires will begin to melt and the coefficient of friction will drop producing a skid or worse.
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