An object with a mass of 6kg is on a plane with an incline of π4. If it takes 24N to start pushing the object down the plane and 9N to keep pushing it, what are the coefficients of static and kinetic friction?

1 Answer
Jun 27, 2017

u(static) = 0.58, u(kinetic) = 0.22

Explanation:

To start motion, Force down = Opposing Frictional Force
Opposing Frictional Force = u(static) Normal Force.
Weight down = mg = 6 (9.8 m/s^2) = 58.8 N
Normal Force is found with trigonometry = 58.8 cos pi/4 =
58.8 [sqrt 2] / 2 = 41.6 N
So .... 24 = u(static) 41.6 => u(static) = 0.58

Similarly 9 = u(kinetic) 41.6 => u(kinetic) = 0.22
:-))