Actually never mind I don't need a picture, the potential energy of a roller coaster is at its lowest point or is the least at the bottom of the lowest point in the roller coast. It is at its greatest at the top of the highest point of the roller coaster.
Explanation: It is at the lowest point. Potential energy is lowest at position D. Gravitational potential energy is based on the mass and height of an object. The height is lowest at this point, so GPE would be lowest also.
