Moment of inertia for rectangular prism

[kingbabi]

I want to find the moment of inertia (a formula) for a beam rotating around the center of a face. In other words, if I'm using http://www.engrasp.com/doc/etb/mod/util1/solidprop/sp005_rectprism/rectangularblock.gif", then I want to find its moment of inertia if its rotated about the POINT Zc, as if a rod were taped onto the center of that face. Thanks!

 

[tiny-tim]

I want to find the moment of inertia (a formula) for a beam rotating around the center of a face. In other words, if I'm using http://www.engrasp.com/doc/etb/mod/util1/solidprop/sp005_rectprism/rectangularblock.gif", then I want to find its moment of inertia if its rotated about the POINT Zc, as if a rod were taped onto the center of that face. Thanks!

Hi kingbabi!

Do you mean about the "vertical" axis through that point and the centre of the prism?

If so, it'll be the same as for a rectangular plate.

 

[minger]

I've had too many problems here at work with moments of inertia (Thanks again Fred). Which moment of inertia are you looking for?

Mass moment, second area moment, polar?