Coefficient of kinetic friction
Given two surfaces, the coefficient of kinetic friction or coefficient of dynamic friction between them is the constant such that, for small speeds of slipping of two bodies with these two as the surfaces of contact, the kinetic friction between the two bodies is times the normal force between the two bodies.
The coefficient of kinetic friction is usually slightly, but not much, smaller than the limiting coefficient of static friction.
Units and dimensions
The coefficient of kinetic friction is a dimensionless scalar and does not need units.
Range of values
|First surface||Second surface||Condition||(radians)||(degrees)||(radians)||(degrees)|
|Aluminimum||Mild steel||Dry and clean|
|Aluminimum||Aluminimum||Dry and clean|
|Copper||Steel||Dry and clean|
|Copper||Copper||Dry and clean||?||?||?|
|Wood||Concrete||Dry and clean||?||?||?|
|Wood||Metal||Dry and clean||?||?||?|
|Wood||Wood||Dry and clean||?||?||?|
|Mild steel||Mild steel||Dry and clean|
|Hard steel||Hard steel||Dry and clean|