Spring in a motionless elevator

[mrshappy0]

Homework Statement

A single mass m1 = 3.1 kg hangs from a spring in a motionless elevator. The spring is extended x = 11 cm from its unstretched length.
1)What is the spring constant of the spring?

Homework Equations

F=-kx

The Attempt at a Solution

Having trouble setting this one up. I know it is easy but the spring confuses me. I drew a free body diagram and I am still lost.

 

[Undoubtedly0]

Hi there! The only forces on the mass will be the weight force (w = mg) pulling down, and the spring force (F = -kx) pulling up. Since the mass is not accelerating, these two forces will be equal and opposite.

 

[mrshappy0]

Yup, got it. -kx=mg. Durrrr. Thanks.