Centroids & Moments of Inertia of Beam Sections

2 2 2 but y dA 0, because the centroid is on this axis, resulting in: IAz 2 o (text notation) or 2 x x Ad y where I o (or I x) is the moment of inertia about the centroid of the area about an x axis and d y is the y distance between the parallel axes Similarly 2 y I y Ad x Moment of inertia about a y axis J Ad 2 o c Polar moment of Inertia 2r 2 d 2 ................
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