As the roller coaster starts to climbs the hill, the potential energy increases again. The potential energy reaches its maximum point when the roller coaster makes it to the top of the hill. At this point, you begin your descent down the first hill. This is where the potential energy transforms into kinetic energy.

Before a roller coaster begins its initial descent, it possesses its maximum amount of gravitational potential energy. As the coaster is pulled up the "lift hill" by a chain or launch system, it is building a "reservoir" of energy based on its position high above the ground. The higher the coaster goes, the more potential energy it accumulates. The formula for this is PE=mgh (Mass × Gravity × Height). Once the car reaches the "apex" or the very top of the hill and begins to tip over, this potential energy is rapidly converted into kinetic energy—the energy of motion. In 2026, modern coasters also utilize "Stored Elastic Energy" or "Electromagnetic Potential Energy" in magnetic launch systems to reach high speeds quickly, but for a traditional gravity-driven coaster, that moment of suspense at the top of the first hill is the point of peak potential energy. This built-up energy must sustain the train through the rest of the track, accounting for energy lost to friction and air resistance.