# 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

 $$\large{ \mu = \frac{F_a}{F_n} }$$

### Where:

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