If two balls of a different size but equal mass roll down the same incline at the same which has more energy? My calculus and physics are weak, but I know that the larger accelerates slower and has a greater moment of inertia. However, will both register the same force on an intervening scale at the bottom? The moment of inertia may be greater for the larger mass, but the forward rate of the smaller is greater at the bottom. I guess my question is, does one have a greater momentum or energy? And why?