As he skates his energy transforms from potential energy to kinetic energy and back again. According to the law of conservation of energy he should keep moving forever, but eventually he comes to a stop. Why does he eventually stop moving? Question 8 options: Friction and air resistance cause some of his kinetic energy to be “lost”. This makes him slow down. The law of conservation of energy does not apply to this situation. The mass of the skateboarder causes him to have less kinetic energy than potential energy so he slows down. One side of the ramp is shorter than the other so he slows down.