- #26

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No, they are not appropriate to this problem. In post #12 the OP makes it clear he is talking about a [thin] wire. This is not a 3D problem. There is no volume and no ##dV##. ##\rho## would be a linear density.In a thread this lengthy, it is not clear to which formulas you are referring.

The general formulas for moment of inertia given by Zondrina in Post #20 would be the correct ones to use.