Physics
posted by Mike Joseph .
A 13.0 kg box is released on a 33 degree incline and accelerates down the incline at 0.20 m/s^2
What is the coefficient of kinetic friction?
* If I know the friction force impeding the object motion is 67 N. How do I find the coefficient of kinetic friction?

m•a=m•g•sinα – F(fr)
F(fr) = m•g•sinα –m•a
F(fr) =μ•N =μ•m•g•cosα
m•g•sinα –m•a = μ•m•g•cosα
μ = (g•sinα –a)/ g•cosα