# Friction Coefficient

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Friction coefficient, abbreviated as $$\mu$$, also called coefficient of friction, a dimensionless number, is the ratio between two contacting surfaces and the frictional force that resists the normal force of the object.

## Friction coefficient formula

$$\large{ \mu = \frac{F_a}{F_n} }$$
Symbol English Metric
$$\large{ \mu }$$  (Greek symbol mu) = friction coefficient $$\large{ dimensionless }$$
$$\large{ F_a }$$ = applied force $$\large{ lbf }$$ $$\large{N}$$
$$\large{ F_n }$$ = normal force $$\large{ lbf }$$ $$\large{N}$$