Physics of roller coasters

Gravity, inertia, g-forces, and centripetal acceleration give riders constantly changing forces which create certain sensations as the coaster travels around the track.

A roller coaster is a machine that uses gravity and inertia to send a train of cars along a winding track.

[1] The combination of gravity and inertia, along with g-forces and centripetal acceleration give the body certain sensations as the coaster moves up, down, and around the track.

Initially, the car is pulled to the top of the first hill and released, at which point it rolls freely along the track without any external mechanical assistance for the remainder of the ride.

This means that the potential energy for the roller coaster system is greatest at the highest point on the track, or the top of the lift hill.

When going around a roller coaster's vertical loop, the inertia, that produces a thrilling acceleration force, also keeps passengers in their seats.

G-forces (gravitational forces) create the so-called "butterfly" sensation felt as a car goes down a gradient.

An acceleration of 1 standard gravity (9.8 m/s2) is the usual force of Earth's gravitational pull exerted on a person while standing still.

However, if the top of a hill is curved more narrowly than a parabola, riders will experience negative Gs and be lifted out of their seats, experiencing the so-called "butterfly" sensation.

As better technology became available, engineers began to use computerized design tools to calculate the forces and stresses that the ride would subject passengers to.