The moment of inertia is the quantity that replaces mass in all the old formulas. Not only is the mass of an object important, but also how that mass is distributed. Find the moment of inertia of a 8 meter long stick with a mass of 40 kg, if it is spun about the center of the stick ISphere = 2/5 MR2 ICylinder = 1/2 MR2 IRing = MR2 IStick thru center = 1/12 ML2 IStick thru end = 1/3 ML2