Physics and Kinetic Friction

Question

A box weighing 500 N is pushed along a horizontal floor at constant velocity by a force of 280 N parallel to the floor. What is the coefficient of kinetic friction between the box and the floor?

Answer 1

The formula for kinetic friction is:

f_k = µ*N

µ: coefficient of kinetic friction

N: normal force

The normal force, N, is 500 N

Since the box is traveling at a constant velocity, F_net = 0

Also,

F_net = F_applied - f_k = 0

Thus,

F_applied = f_k

F_applied = 280 N = µ * 500 N

µ = 280/500 = 0.56