Okay, I have a ball balanced on a pole. The P.E. is given as 30 J. At the bottom of the pole, if it were to fall off, what would the P.E. be? I say zero. Okay, but now the ball is setting on top of a series of steps. The topmost step is the same height as the pole was, so I am guessing the ball has 30 J P.E. again. But, if it goes to the next step (three steps total, it is setting on the top one), I mean falls down to that step and sticks, is the P.E. one-third as much since it is one-third of the way down, or two-thirds as much, seeing as it is still 2/3 of the way up? It is going down, yes, but it's still 2/3 of the way off the ground. Does the 5dt^2 thing have anything to do the the ball now?