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## Homework Statement

http://www.aapt.org/physicsteam/2010/upload/2010_FmaSolutions.pdf

See Number 24

## Homework Equations

CoM = M1x1 + M2x2 / (M1+M2)

MOI_disk: 1/2mr^2

## The Attempt at a Solution

So what I was thinking was find the new CoM then use the parallel-axis theorem.

To find the new CoM:

MsXs + MbXb / (Ms + Mb) = 0, where s is the small unshaded part, and b is the big, shaded portion.

MsXs = - MbXb

Xb = -Ms/MbXs

Xb = (-R)(ρ∏R^2) / ρ(∏(2R)^2 - ∏R^2)

Xb = R/3

Parallel Axis Theorem will smaller mass:

1/2MR^2 + 1/9MR^2

11/18MR^2

Yeah I'm pretty lost. I feel like there is a much better solution.