# Static Friction Coefficient

Written by Jerry Ratzlaff. Posted in Dimensionless Numbers

Static friction coefficient is a dimensionless number, the amount of force that resists motion that is on the verge of motion.

## formula

$$\mu_s = \frac {f_s}{F_n}$$

Where:

$$\mu_s$$ (Greek symbol mu) = static friction coefficient

$$f_s$$ = static friction

$$F_n$$ = normal force