Question

An object with a mass of `16 kg` is lying still on a surface and is compressing a horizontal spring by `7/8 m`. If the spring's constant is `12 (kg)/s^2`, what is the minimum value of the surface's coefficient of static friction?

Answer 1

`0.067`

Explanation:

The force exerted by a spring with spring constant `k` and after a compression of `x` is given as `-kx`.

Now, as friction is always in the opposite direction to the applied force, hence, we have

`muN = kx`

where `N` is the normal force `= mg`

hence,

`mu = (kx)/(mg) = (12*7/8)/(16*9.8) ~~0.067`