What is the friction force

Question

A 25 kg wooden crate is being pushed against a large spring with a spring constant of 1200 N/m. If the coefficient of friction between the crate and the ground is 0.68, how
much does the spring have to be compressed to balance out with the friction force

Answer 1

Set the magnitude of the friction force equal to the magnitude of the spring force, and solve for the spring compression distance.  I am assuming everything is in the horizontal direction.

 

μmg = kx

 

x = μmg/k = (0.68)(25 kg)(9.8 m/s²) / (1200 N/m) ≅ 0.1388 m