Question

An object with a mass of `7 kg` is lying still on a surface and is compressing a horizontal spring by `5/4 m`. If the spring's constant is `4 (kg)/s^2`, what is the minimum value of the surface's coefficient of static friction?

Answer 1

The coefficient of static friction is `=0.073`

Explanation:

The force of compression is

`F=kx=4*5/4=5N`

The coefficient of kinetic friction is

`mu_s=F/N`

The normal force is `N=mg=(7g)N`

So,

`mu_s=5/(7g)=0.073`