# How to find the moment of inertia of a cut-out object?

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I've been trying to solve this question for a day now. Can someone point me in the right direction? I'd really appreciate it!

I've been trying to solve this question for a day now. Can someone point me in the right direction? I'd really appreciate it!

##### 1 Answer

#### Explanation:

The center of mass of the original triangle (the part that has been cut out) was at the center of the circle, at a distance

The moment of inertia of the whole system is thus the same as that of the complete circular disc about the pivot.

This is

(using the parallel axis theorem and the known result that the moment of inertia of a uniform circular disc about an axis passing through its center and normal to it is