How A Roller Coaster Works

Roller Coasters originated from the ice slides built in Russia during the 1400’s, today we see these large structures at Amusement parks across the country. Some roller coasters are those large steel or wooden structures that people like to sit in a

cart or car going up and down the humps and hills giving them a thrill of a ride. The ride may not last all that long, but for some the time seems forever when you are quite scared and your stomach seems to be caught up in your throat. Many of us may or may not want to know exactly how a roller coaster works, because we may not want to ride one again. For some, the understanding of “How does a roller coaster work?” is thrilling in itself. Let’s use physics to further understand this exciting ride.

You may or may not know this, but as your cruising down the roller coaster structure at a high speed of 50-60 miles per hour, there is no engine. Let me further explain. The train of cars is initially taken up the lift hill or the first hill by a chain.

The energy flows from the electric field (the space surrounding an electric charge) into the mechanical turning of the motor driving the chain. The chain lifts the cars; the kinetic energy of the motion of the chain is given to the train. This energy, in turn, flows into the gravitational field (the force field that describes the acceleration of gravity in a region of space) while the coaster makes it way to the highest point or top of the roller coaster structure, then the chain disengages. The train is moving quite slow at this point. Its maximum energy for this ride is stored in the gravitational field.

Eventually, the train of cars will begin to fall, the kinetic energy (motion of the train of cars) increases as the gravitational potential (gravitational field) energy decreases. As the train of cars hit the bottom of the first hump or hill, the velocity and the kinetic energy are the greatest and the gravitational energy is spent. Inertia is what takes the train cars though the rest of the track.

The weight of the train car is what gives it inertia. Without that it would not have any speed to get up the next hill this is sometimes known as momentum. As the train of cars climbs the next hill, most of the kinetic energy is transferred to the gravitational field. The velocity decreases. This continues for some time.

There is friction, wind resistance, track friction causing some thermal heating along the way. All the humps or hills after the first one are successively shorter. Ultimately the gravitational and kinetic energies used at the top of the lift hill move into thermal energy by the end of the ride. This energy is no longer available to roller coaster system. Roller coasters are really heaters, allowing for the flow of electrical energy into heat, by way of kinetic energy and the gravitational field.

We mentioned there are two types of roller coasters, wooden structures and steel coasters. You will usually see wooden coasters with no looping. They are also not as tall and fast as steel coasters. Wooden coasters do offer one advantage to the roller coaster junkie; they sway lot more than steel structures. Steel coasters allow for a bit more creative designing of loops, steeper hills and the exciting drops, rolls and of course the speed.
There does happen to be wheels on the train cars and they do have a huge part in the success of your roller coaster ride too. There are several different types of wheels to help keep the ride smooth.

Basically, there are three sets of wheels, top, bottom and side. The top wheels are referred to as the rollers, the bottom wheels are the up-stop and the side wheels are the guides, assisting in the moving from side to side or swaying of the cars. The wheels can be made out of several different materials, including steel and neoprene. If plastics are used, the coaster is electrically grounded just before it goes through proximity sensors. This will keep the sensors from shorting out.

In addition, we need to be concerned with the braking system. Yes, there is a braking system designed with a roller coaster. The common one has a fin of steel hanging from the center of each train car. The brake pads are between the tracks. As the fin passes through the pads, the fins are squeezed to slow the train. When the pads are open, the train of cars moves freely through the track.

Roller coasters overall are quite simple in how they operate, but there is much more to make the ride as thrilling as possible for the many patrons and roller coaster junkies that ride them. Designers today are constantly looking at how they can “add” to the ride. We now have more roller coasters today with more loops and hangs; some even have sound and visual effects.

1) Franks, jack. “Ask A Scientist”. D.O.E. June 3, 2007 .
2) Blonghtf, Lee. “Roller Coaster”. June 3, 2007 .
3) Smilkins, Jude. “X-tream Science”. U Of Wisconsin. June 3, 2007 .
4) SCI, FI. “Tech”. NASA. June 3, 2007 .