Potential energy is stored energy that an object has due to its position or chemical composition, while kinetic energy is the energy of motion. A roller coaster car has kinetic energy as it moves down the track, and potential energy as it slows to a stop at the top of a hill where it is positioned to move downward. Substances like wood, coal, oil and gasoline have potential chemical energy stored in their molecular bonds that can be released as heat energy through burning. Potential and kinetic energy can be converted between each other.