Rotational Inertia worked it many times.

[1MileCrash]

Homework Statement

In the figure below, the pendulum consists of a uniform disk with radius r = 10 cm and mass 480 g attached to a uniform rod with length L = 500 mm and mass 260 g.

Homework Equations

The Attempt at a Solution

I'm going to cut to the chase.

I'm basically going with:

I = 1/2MR^2 + M(R+l)^2 + ml^2 / 3

Where M and R are mass and radius of disk and m and l are mass and length of rod.

My final answer has come to .14653 every time, and it is wrong.

 

[1MileCrash]

They snuck cm/mm in there, never mind.



Bastards.