# An object with a mass of # 3 kg# is lying on a surface and is compressing a horizontal spring by #20 cm#. If the spring's constant is # 9 (kg)/s^2#, what is the minimum value of the surface's coefficient of static friction?

##### 1 Answer

#### Answer:

The minimum value of the coefficient of static friction is 0.06.

#### Explanation:

I assume that it is to be understood that you are asking for minimum value of the surface's coefficient of static friction *that will prevent the spring from moving the mass*.

The spring exerts a horizontal force of

Friction needs to be able to oppose that force with an equal and opposite force to maintain its grip. The force of friction is

where N is the component if the object's weight normal to the surface. I assume the surface is horizontal, so N is the object's full weight.

Solving for

I hope this helps,

Steve