# An object with a mass of # 3 # #kg# is lying on a surface and is compressing a horizontal spring by #10 # #cm#. If the spring's constant is # 9# #kgs^-2#, what is the minimum value of the surface's coefficient of static friction?

##### 1 Answer

Apr 7, 2016

#### Answer:

The frictional coefficient

#### Explanation:

(convert the distance to SI units:

The force exerted by the spring is given by:

Since the object is stationary, this force applied by the spring must be being balanced by the frictional force.

The frictional force is given by:

And the normal force is the gravitational force:

Rearranging:

(frictional coefficients do not have units)

(side note: I keep saying that