# Calculating the Coefficient of Friction

*Most recent answer: 04/30/2020*

Q:

Is there a way to calculate the coefficient of static friction between a tire and a road, given the car's initial speed of 0 m/s, a final speed of 27.77778 m/s, and a change in time of 2.45 seconds? Is there a way to generate a formula to solve for this component?

- Robert Stewart (age 17)

Bel Air, MD, USA

- Robert Stewart (age 17)

Bel Air, MD, USA

A:

The coefficient of static friction tells you the maximum acceleration the car can undergo before the tires begin to slip (*i.e.*, "squealing" the tires). For a given acceleration without slipping, we can only calculate the minimum coefficient that will enable it.

In this problem, *a* = 27.77778 m/s / 2.45 s = 11.34 m/s^{2}, a bit more than 1 g. The definition of the friction coefficient is *F*_{max} = *ma _{max}* = μ

*m*g --> μ =

*a*/g > 11.34/2.45 = 1.16 . All we know is that μ must be larger than this, because

_{max}*a*

_{max}>

*a*.

*(published on 04/30/2020)*