Before begining, I would like to point out I did look at the following thread previous to this one, and thus have a few questions about that thread and it's application to this one: https://www.physicsforums.com/showthread.php?t=143536 1. The problem statement, all variables and given/known data The problem: http://img122.imageshack.us/my.php?image=bphysicsry1.png 2. Relevant equations Not quite sure, but I think this one comes into play: http://hyperphysics.phy-astr.gsu.edu/hbase/pendp.html 3. The attempt at a solution Alrighty, I looked through the thread mentioned above, and while the problems are similar, there is one notable exeption here. In the other thread's problem, I was given. In my problem, I is not given, and the spring is not acting through the CoM So, my question is, does the pendulum equation still work? And is I support merely 1/3mL2? And which length is l, the entire length of the bar, or the length of the spring to the pivot point? If not, how do I find I? I will say I'm slightly confused about the other thread, as I don't really get the "parallel axis theorem" or the more complicated matters of moment of inertia. Any help would be appreciated. One other thing, I'm also confused as to what should go on the bottom of the equation. I know it says "mgh", but since the spring is doing the pendullum motion, I'm not sure. Also, how the heck am I supposed to calculate a spring force without the displacement?