[SOLVED] a tricky Moment of Inertia question, help needed... The question is in the JPG attachment. This is what i tried: Obviously the side which is right on the axis has no moment of inertia so we're left with the 2 horizontal ones and the other vertical. for the two horizontal sides we've got an equation: (M*L^2)/3 and we consider it twice. the last side is probably where i went wrong - i thought it's simply M*L^2 because it can be regarded as a point mass at distance L but that didn't work. then i tried using the parallel axis theorem but that didn't help too. Any thoughts? i'm sure its really easy for most of you guys... Thanx.