# Homework Help: Question relevant to Moments of Inertia

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1. Nov 1, 2014

### Aristotle

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

2. Relevant equations
I= ∑ miri^2 ?

3. The attempt at a solution

I'm not sure on how to start this problem. How exactly do I know which one is IA, IB, IC since it didnt specify? Can somebody please hint me in solving this problem?

Last edited: Nov 1, 2014
2. Nov 1, 2014

### haruspex

There's no way to know for sure, but I would guess they are A, B, C from left to right.
By the way, this belongs in Introductory, not in Advanced.

3. Nov 1, 2014

### Aristotle

Oh I'm sorry about that, how do I move the thread over? Kinda new to this.

4. Nov 1, 2014

### haruspex

I don't know whether you can. Might need a Mentor for that. But don't worry about it this time.. just consider it next time.
Not sure what the exact definition of Advanced is here, but if you look around the other posts you'll get the flavour.

5. Nov 1, 2014

### Aristotle

Ah okay. Do you think you can help me with the question though? I'm not really sure where to begin.

6. Nov 2, 2014

### haruspex

Let's start with the leftmost picture (A, presumably). There is only one mass. What is the mass, and how far is it from the axis? What does the ∑miri2 formula give you?

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