Gravitational potential energy is greatest at the highest point of a roller coaster and least at the lowest point. Kinetic energy is energy an object has because of its motion and is equal to one-half multiplied by the mass of an object multiplied by its velocity squared (KE = 1/2 mv²).

Gravity affects a roller coaster most significantly at the apex of the lift hill and throughout the first major drop. Once the coaster train is released from the chain lift at its highest point, gravity becomes the primary "engine" of the ride, converting the accumulated potential energy into kinetic energy. At the very top of a hill, gravity's pull is what initiates the acceleration, but it is at the bottom of the valleys between hills where the interplay of gravity and centripetal force is most physically felt by passengers. In these dips, the combination of the downward pull of gravity and the upward push of the track creates high "G-forces," making riders feel much heavier than normal. Conversely, at the crest of "airtime" hills, gravity is momentarily countered by inertia, leading to the sensation of weightlessness or "negative Gs." Engineers meticulously calculate these gravitational effects to ensure the train has enough momentum to complete the circuit while keeping the physical stress on the riders within safe and thrilling limits.