Hi Folks,(adsbygoogle = window.adsbygoogle || []).push({});

I am designing a piece of kinetic scultpure that will involve cubes made from aluminium square tubing rotating around an axis that passes through two diagonal corners. I am trying to determine motor size to drive this thing, and to do that I need to know its moment of inertia.

Math is not a strong point for me AT ALL. I don't even know what the symbols in the calcualtions for determining moment of inertia simple shapes represent. So while I would like to understand the calculation I'd request that I am not bamboozled by the theory.

So lets begin. Lets say my material has a mass of Q per meter. The cube side has a length of L. Most confounding for me (as I have not found an example of this elsewhere) the axis of rotation passes through two diagonal corners.

So lets say a cube L of 1000mm and the tubing is 50mm x 50mm (not sure if this is important)

The axis of rotation is the thin light grey line in the next image..

[URL]http://fle33.com/uploads/mi_cube.jpg[/URL]

Any help is greatly appreciated.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Moment of inertia for a hollow cube. Rotating about diagonal opp corners

**Physics Forums | Science Articles, Homework Help, Discussion**