The movement of a roller coaster is accomplished by the conversion of potential energy to kinetic energy. The roller coaster cars gain potential energy as they are pulled to the top of the first hill. As the cars descend the potential energy is converted to kinetic energy.

A traditional roller coaster needs potential energy because it typically lacks an engine to propel it through the entire circuit; it relies on the conversion of energy to move. The process begins with a "lift hill," where a chain or cable pulls the train to the highest point of the ride. As the train rises, it accumulates gravitational potential energy (U=mgh, where m is mass, g is gravity, and h is height). Once the train reaches the apex and begins to drop, this stored potential energy is converted into kinetic energy (the energy of motion). In 2026, engineers design tracks so that the train always has enough kinetic energy to make it over the next hill, though some energy is always lost to friction and air resistance. Without that initial massive "bank" of potential energy at the start, the coaster would not have the "fuel" needed to navigate loops, turns, and corkscrews. While modern "launched" coasters use magnets to provide immediate kinetic energy, the classic coaster experience is essentially a physics lesson in the continuous, thrilling exchange between "stored" and "active" energy.