A horizontal plank of mass m and length L is pivoted at one end. The plank's other end is supported by a spring of force constant k. The moment of inertia of the plank about the pivot is I = 1/3mL^2. The plank is displaced by a small angle (theta) from horizontal equilibrium and released. Find the angular frequency (omega) of simple harmonic motion. (Hint: consider the torques about the pivot point.)