How Do You Calculate Angular Frequency in Simple Harmonic Motion?

[myoplex11]

Homework Statement

A horizontal plank (m = 2.0 kg, L = 1.0 m) is pivoted at one end. A spring. (k = 1000N/m) is attached at the other end find the angular frequence for small oscillations?

Homework Equations

w=(k/m)^0.e\5

The Attempt at a Solution

w= (1000/2)^0.5
i have no idea is this a pendulum problem i tried the w=(mgd/I)^0.5 and that also did not work. How do i go about this problem thanks

 

[rl.bhat]

Weight of the plank acts through the CG of the plank.Clock wise moment due to this is 0.5*2*g. If the plank remains horizontal ,anticlockwise moment due to reaction in the spring = F*1 = F = mg = 0.5*2*g. So the spring appears to be stretched by a mass of 1 kg. using this value find w.