Force = mass x acceleration. If you think back to freshman physics, that's the basic formula that determines how much energy is being exerted on an object when it's struck by something in motion. Catch a baseball and you can feel the force striking the palm of your hand. That pain is wasted energy, and in the world of hybrids – from cars to trains – it's energy that could be harnessed, saved and deployed later on. That's what GE is trying to demonstrate with the video below, calculating how much force is being applied to a cylinder of ballistic gel and showing how much of energy is lost when the same objects encounter something... less forgiving.