Question

1. An object is on an 25 degree incline. The force of friction up the incline is 8.0 N?

A. What is the acceleration of the block?
B. What is the coefficient of the kinetic friction?

Answer 1

Weight is m g
Component of force (of weight) parallel to incline is m g sin(25)
Component of force (of weight) normal to incline is m g cos(25)

acceleration = (force parallel to incline)/(mass of block) = [m g sin(25) - 8N]/m

mu = friction / normal force = 8 N / m g cos (25)