Question

An object with a mass of `18 kg` is lying on a surface and is compressing a horizontal spring by `40 cm`. 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 `=0.01`

Explanation:

The mass is `m=18kg`

The compression of the spring is `x=0.4m`

The spring constant is `k=4kgs^-2`

The reaction of the spring is `R=kx=4*0.4=1.6N`

The acceleration due to gravity is `g=9.8ms^-2`

The normal reaction of the object is `N=mg=18*9.8=176.4N`

The coefficient of static friction is

`mu_s=R/N=1.6/176.4=0.01`