Misplaced Pages

Revision as of 23:20, 8 July 2010

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages) No issues specified. Please specify issues, or remove this template. (Learn how and when to remove this message)

Simply speaking, a roller coaster is "a machine that uses gravity and inertia to send a train along a winding track." This 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. Gravity causes the forces against a rider to constantly change. This is what causes the ride to be so enjoyable or, for some, nauseating. The basic principles of roller coaster mechanics have been known since 1665, and since then roller coasters have become a popular diversion.

Centripetal acceleration

Centripetal acceleration results from moving in a circular path. The "force" points toward the center of the track, but is felt by riders as a force pushing them toward the outer edge of the car. However, centripetal acceleration is not actually a force but is the body’s inertia, or resistance to the coaster's change in direction. The following is an equation expressing centripetal acceleration: ${\displaystyle a}$_r${\displaystyle =v}$${\displaystyle /r}$, where a_r is centripetal acceleration, v is velocity in meters per second, and r is the radius of the circle in meters. This means that the higher the train, the greater the velocity and the greater the centripetal acceleration. This is shown by the equation for potential energy: ${\displaystyle U}$_g =${\displaystyle mgh}$, where U_g is potential energy, m is mass in kilograms, g is acceleration due to gravity, and h is the distance above the ground in meters. This also means that the smaller the curve of the path being traveled, the greater the centripetal acceleration.

Energy

Roller coasters have no engine; rather, the car is pulled to the top of the first hill, but after that, the coaster must complete the ride on its own. The law of conservation of energy states that energy can neither be created nor destroyed, thus, the purpose of the ascent of the first hill is to build up the potential energy of the ride that will then be converted to kinetic energy as the coaster goes down the hill. The initial hill, or the lift hill, is the tallest in the entire ride. As the train is pulled to the top, it is gaining potential, or stored energy. Because mass and gravity are constant for the train, if the height of the train above the ground is increased, the potential energy must also increase. 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. As the roller coaster train begins its descent from the lift hill, its velocity increases. This causes the train to gain kinetic energy, which is the energy of motion. The faster the train moves, the more kinetic energy the train gains.

This is shown by the equation for kinetic energy, ${\displaystyle K=1/2mv}$, where K is kinetic energy, m is mass in kilograms, and v is velocity in meters per second. Bemcause the ass is constant, if the velocity is increased, the kinetic energy must also increase. This means that the kinetic energy for the roller coaster system is greatest at the bottom of the highest hill on the track, or the bottom of the lift hill. When the train begins to climb the next hill on the track, the train starts to slow down, thereby decreasing its kinetic energy. This process continues with each hill. The energy is never destroyed, but is weakened because of the friction between the car and track. Brakes ultimately bring the ride to a complete stop.

Inertia and Gravity

When going around a loop of a roller coaster, passengers' inertia not only produces a thrilling acceleration force, but also keeps them in their seat. As their car approaches a loop, passengers' inertial velocity is straight ahead but since the track pulls the coaster up, they go up as well. The force of the car's acceleration pushes passengers up off the coaster floor while the inertia pushes them back into their seats. Gravity and acceleration forces push passengers in opposite directions with nearly equal force, creating a weightless sensation. At the bottom of a loop, gravity and acceleration push passengers down, causing them to feel very heavy. Most roller coasters require passengers to wear a safety harness, but the forces exerted by most loop-the-loop coasters would keep passengers from falling out.

G-forces

G-forces create the so-called "butterfly" sensation felt as a car goes down a hill. A force of 1 G is the usual force of Earth’s gravitational pull exerted on a person while they stand still. In other words, it is just the person's weight, since one does not feel the effects of gravity while just standing. When a person feels weightless (at the top of a loop or while going down a hill), they are experiencing 0 Gs. However, if the top of a hill is curved more narrowly then a parabola, riders will experience negative Gs and will actually be lifted out of their seats, experiencing the so-called "butterfly" sensation.

Difference between wood and steel coasters

Wooden and steel coasters work the same way, but they have different thrill seeking abilities. Steel coasters have the highest drops, most loops, are faster, and can even be designed so that the coaster hangs below the track, or so that the riders stand instead of sit.

Wooden coasters, however, are not as fast, not as high, and usually do not contain loops. The beams and struts of a wooden coaster make up a solid support for the cars and riders but the coaster still does not look sturdy or safe. Intellectually, riders know it is safe, but psychologically they do not. This creates a fear factor. Because the structure is fairly inflexible, wooden coasters tend to sway, which also adds to the thrill and gives the body a complete different sensation than going up, down, and around usually would.

A history of roller coasters

The first roller coaster was designed in 1610 in St. Petersburg, Russia. A showman formed a steep incline by placing a wooden slide over a wood frame. He then poured water on it so it would freeze. People would then slide down this frozen hill on their sleds. As more were built, they became known as the Russian Ice Slides. Empress Catherine the Great was so thrilled by this contraption that she wanted to use it during the summer too. Her request was met, and the first wooden cart was designed to carry the monarch down the slide. This wooden slide design soon turned into wooden towers, and following that, the first looping ride was designed in 1846, at the Frascati Gardens in Paris. However, this looping ride was nothing like loops we see today. People would ride down a 43-foot (13-metre) high railway track in wicker carriages through a 13-foot (4.0-metre) loop. At the time, other looping rides consisted of people rolling down tracks while strapped into a wooden barrel. LaMarcus Adna Thompson built the first modern coaster in 1884, called Switchback Railway. The ride, located at Coney Island, consisted of two wooden towers that were 45 feet (14 metres) high and 450-foot (140-metre) apart and connected by a flat steel track laid over five to seven wooden planks. The ride went just over 6 miles per hour (9.7 km/h). There was no way to get the coaster up the hill before it went down so riders had to climb a staircase and board a single ten-passenger car to ride the first part of the ride. Then workers would push the cart up to the second hill and riders would climb another staircase to finish the ride. This ride became so popular that they began charging a nickel to ride. After WWI, builders started to make coasters with four to six carts per train. Amusement parks began to compete to see who could have the tallest, fastest coaster. At the time safety was not a concern, and a lap bar and strong grip were all that riders had to depend on to keep them safe. Obviously, these were not enough, and many injuries and deaths occurred. Even then, riders did not stop riding; in fact, after a well-publicized incident, the lines for these dangerous rides grew longer and longer. Proprietors even hired a full-time nurse to treat injured riders.

Technology

As better technology became readily available, engineers began to use computerized design tools to calculate the forces and stresses that the ride would subject riders to. Specially designed restraints, lightweight and durable materials, and computers are now used to design safe coasters. Today, tubular steel tracks and polyurethane wheels that allow coasters to go about Template:Conert are used to construct the roller coasters that are getting increasingly taller, faster, and more complex. Take for example, the Colossus and X2 at Six Flags Magic Mountain in Valencia, CA. The Colossus was built in 1978. At that time, it was the world’s largest roller coaster. Currently, it is still the fastest wooden roller coaster in the west. It exerts a G-force of 3.23 Gs.

References

1. Harris, Tom. "How Roller Coasters Work". Retrieved 1 July 2010. At its most basic level, this is all a roller coaster is -- a machine that uses gravity and inertia to send a train along a winding track.
2. Annberg Media, (n.d.). Roller Coaster. Interactives, Retrieved Mar. 25, 2009.
3. Howe, George. The Physics of Fear. Aug. 1993. Academic Search Premier. EbscoHost. Leid, Las Vegas. 23 March 2009.
4. Harris, Tom. Inside This Article. How Roller Coasters Work. How Stuff Works. 19 March 2009.
5. Meredith, Neil J. The Roller Coaster: Architectural Symbol and Sign. The Journal of Popular Culture. 15: 108-15.
6. Wiley InterScience. 5 March 2004. 24 March 2009
7. Sastamolnen, Shawna. The Science Behind the Thrills. Roller Coaster Physics. Fall 2002.
8. Valenti, Micheal. Designing the Ultimate Thrill Machine. Aug. 1995. ProQuest.Leid, Las Vegas. 24 March 2009. (n.d.). Retrieved 1996, from

• Roller coasters