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1. The problem statement, all variables and given/known data

Four point masses of 3.0 kg each are arranged in a square on mass-less rod. The length of a side of the square is .50 m. What is the rotational Inertia for rotation about an axis passing through masses A and C?

A B

D C

2. Relevant equations

I=mr^2

3. The attempt at a solution

I have the solution but just don't understand it! I cant on my own find the radius if it's in a diagonal problem like this one. For B and D, the radius is .5m * [itex]\sqrt{}2[/itex] / 2.

Where does the [itex]\sqrt{}2[/itex] / 2 come from?

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# Rotational Inertia Four point masses problem-diagonal

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