My dad came back from his "business trip" with a group of his friends two weeks ago. This is a clip from their second day, trying to outdo each other... I couldn't really open up my camera to show the capacitor, so I'm just going back to projectiles, potential and kinetic energies, and gravity. When he approaches the ramp, most, if not all, of his energy is now kinetic. After he hits the jump, gravity is the only force acting upon him (a=9.80 m/s). At the top of the jump, the vertical velocity is zero and he begins to drop. When he hits the ground, he still has momentum and energy, and thus bounces off. (It left a huge bruise on his leg...they took a picture.)