Have you ever wondered why rollercoaster cars don't have engines? Vehicles don't always need that kind of power to make them go. But they do need energy of some sort. Before a rollercoaster ride begins, an electric winch winds the cars to the top of the first hill. That can take a while, because some rollercoasters start off nearly 100m (330ft) in the air!
The winch has to use energy to pull the rollercoasters up the hill, but that energy doesn't simply disappear. The rollercoaster cars store it just by being up in the air—and the higher up they are, the more energy they store. They'll use the same energy to race back down the hill when the ride begins. Because they have the ability (or potential) to use in the future energy that was stored…show more content… They can never have any more energy than this, no matter how long the ride lasts. Throughout the ride, they are constantly swapping back and forth between potential and kinetic energy. Each time they race up a hill, they gain more potential energy (by rising higher in the air), but they compensate for it by losing some kinetic energy too (by slowing down). That's why rollercoaster cars always go slower in the higher bits of a ride and faster in the lower bits. The coaster tracks serve to channel this force, they control the way the coaster cars fall. If the tracks slope down, gravity pulls the front of the car toward the ground, so it accelerates. If the tracks tilt up, gravity applies a downward force on the back of the coaster, so it decelerates. Since an object in motion tends to stay in motion (Newton's first law of motion), the coaster car will maintain a forward velocity even when it is moving up the track, opposite the force of gravity. When the coaster ascends one of the smaller hills that follows the initial lift hill, its kinetic energy changes back to potential energy. In this way, the course of the track is constantly converting energy from kinetic to potential and back again. In most roller coasters, the hills decrease in height as you move along the