Relating moment of Inertia and pendulum oscillation!

1. Nov 18, 2012

heatherro92

I took a picture of the question to help.

I know that the moment of inertia for a rod (at one end, not the center) is:
1/3ML^2

And I know that the period of oscillation is:
T=2∏√(L/g)

But I don't know how to relate them... I tried doing Torque=Iα=Fdcosθ and solve in terms of Time.... but it wasn't becoming the equation and I had a random ω I couldn't get rid of. And I don't think I'm allowed to use the oscillation equation at all since I'm supposed to be deriving it, I'm just not sure what to do.

2. Nov 18, 2012

ehild

3. Nov 18, 2012

heatherro92

so am I solving for α in that equation and that's identical to the period?

4. Nov 18, 2012

ehild

No, α is the angular acceleration. The period is T.

ehild