Finding resonance frequency of a hanging mass on a spring

[Turion]

Why did they calculate angular frequency if the question asked for frequency?

Also why is kx=mg? Wouldn't that mean the spring is at equilibrium?

 

[barryj]

You can express frequency as rad/sec or rev/sec.

Also why is kx=mg? Wouldn't that mean the spring is at equilibrium?
In this case the spring is at equilibrium but this relationship allows you to get an expression for k/m and this is needed to get the frequency.