# Rolling things

i know that the equation for rotational inertia of a hoop is different than the equation for a solid cylinder, but what is the equation for a rectangular cube in a hoop?
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\ (|) <--is what I mean if the diagram helps at all
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Doc Al
Mentor
I have no idea what that diagram is supposed to show, but the rotational inertia of a compound object is just the sum of the rotational inertias of each component. The rotational inertia of a cube of side s about an axis perpendicular to a face and passing through its center of mass is: $1/6 m s^2$

What do you mean by the term 'rectangular cube'?