The above spring has a spring constant of 29 N/m. The μ between the box and the surface is 0.3. The box has a mass of 1 kg.
What is the maximum distance that the spring can be stretched from equilibrium before the box begins to slide back?
weight = m g = 1*9.81 = 9.81 N
max friction force = .3*9.81 = 2.94 N
2.94 = k x = 29 x
x = .101 meter = 10.1 cm