Three forces viz; inertial, gravitational and centripetal forces come into play while giving you a great ride on board rollercoaster. You may mentally connect a rollercoaster with a passenger train consisting of connected compartments that run on tracks. However unlike a passenger train, there is no engine or power source involved in a rollercoaster.
The 'initial lift hill' (the time when the coaster is pulled up the first hill) is done to build up a stock of potential energy. After that for most part of the ride, the rollercoaster moves by the forces of gravity and inertia. As the coaster rises up in the air, gravitational forces start to work, applying a constant downward motion on the coaster. In other words, the potential energy you build while going uphill is released as kinetic energy to take you down-hill. The top of the first hill or the highest point on the track is the place where the roller coaster's gravitational potential energy is the highest. Each time the roller coaster goes downhill, the gravitational potential energy reduces and its kinetic energy increases.
The 'initial lift hill' (the time when the coaster is pulled up the first hill) is done to build up a stock of potential energy. After that for most part of the ride, the rollercoaster moves by the forces of gravity and inertia. As the coaster rises up in the air, gravitational forces start to work, applying a constant downward motion on the coaster. In other words, the potential energy you build while going uphill is released as kinetic energy to take you down-hill. The top of the first hill or the highest point on the track is the place where the roller coaster's gravitational potential energy is the highest. Each time the roller coaster goes downhill, the gravitational potential energy reduces and its kinetic energy increases.