The friction needed to start a body at rest into motion. The coefficient of static friction satisfies

where is the coefficient of kinetic friction. Some values for common substances are summarized in the following table (Weast 1981, pp. F-21 to F-23).

substance
wood on wood	0.25-0.50
steel on steel	0.58
glass on glass	0.9-1.0

Friction, Kinetic Friction, Starting Friction