Physics Comprehensive Assessment Module

Physics Comprehensive assessment Module

Roller Coasters

Shawn-Alexandre Lennox

Kerr Canning

Physics NYB

March 18th, 2003

Roller Coasters

This paper will be all about roller coasters. It will give explanations on how they work, but will also establish the many links they have with different branches of sciences, notably physics, math and biology. Roller coasters, their designs and up keeping all depends on these various branches of sciences. This project will link all of the sciences together and show how complicated a roller coaster can really be.

The basics:

To start off, roller coasters are defined as “an amusement park ride consisting of a narrow rail track on a metal framework shaped into extreme peaks and troughs and sharp bends” [4]. That was the official definition, but everyone can associate some feelings when they hear the word roller coaster. They immediately think fun, danger and extreme sensations. People who are more afraid might feel sick and dizzy thinking about them, because after all, roller coasters are not for everyone.

Roller coasters come in all sorts of shapes and sizes, all having their own special effects. Each one may seem the same to some extend, but each coaster is different. There are different types of coasters. Some classic ones are made out of wood, and most new ones metal, or a metallic alloy. In some you sit down in a chair and you are in a little cart. In others, you might have your feet dangling and the track over your head, or been standing on some platform being tossed around everywhere [2]. Whatever the type of coaster it is, they all have sensibly the same result: powerful sensations that drive the spectator crazy. In the end, the goal of a roller coaster is to give the appearance of danger, without it being dangerous.

The physics:

It is pretty obvious, and a fair estimate to say that physics has a lot to do with roller coasters. The laws of physics dictate how coasters work, and it is basically, most of the time, thanks to physics that coasters function with so little mechanisms to power the coasters. Actually, it’s thanks to gravity, but physics help us control gravity and use it to our advantage.

Let’s look at a first obvious link to physics. “What goes up must come down,” is a very famous saying that Sir Isaac Newton has made popular, and he couldn’t be more right. Quick proof that this is true to coasters: when was the last time anyone saw a roller coaster that neither went up or down? Never. Simple theory behind this, what most people who do a low level physics course will know, potential and kinetic energy. As an object gets higher and higher, it increases its potential energy (mgh) and as it goes faster and faster, it increases its kinetic energy (1/2mv2). During a roller coaster ride, energy is constantly converted from potential to kinetic energy, and vica versa. As a coaster goes up, it gains potential energy. That’s why a coaster almost always goes up first, pulled by a chain. It is given the energy to go up, attains a certain amount of potential energy, then can start going down and transforming it into kinetic energy. Going down energy goes from potential to kinetic, and as it’s going up, kinetic into potential. This is basically the theory that keeps a roller coaster going, and is the reason for the “main climb”, be it at the beginning or in the middle, there is always one.The coaster grips on to a chain of some sort to get it up because it doesn’t have enough energy to go up by itself. One must also remember that energy is not created nor lost, that’s why the chain “gives” energy to the coaster. On the occasion, you might see a spinning wheel here and there pushing the coaster forward some more, but it’s just giving the coaster a little more energy, or recharging it you could say (since there are many factors that make for the dissipation of energy, such as heat from friction).

The mathematics:

Mathematics is also one of the many parts the backbone of a coaster has. Although we may not realize it as much, or can’t see it, and even take it for granted, coasters would not exist had it not been for mathematics. Everything has to be calculated, and it’s as simple as that. Before a coaster is made, models are made and tested. Everything has to work before they build it, so they must “create” the ride virtually and make sure it works fine at every moment. This is only achieved through mathematical models and the laws of math. The laws of math they use and types need not be specified, as the important point is to realize that they do use them. In any case, this is a very important step of the progress. Since it has not been applied in reality yet and a mistake in the mathematics in the computer is not be detected, a small error anywhere in the in the mathematical theoretical portion of the project, could lead to huge catastrophes in the real world where the coaster could be built only to come crashing down, killing many people.

Mathematicians must predict all sorts of things. Such as the speed at certain points, or the acceleration, all the forces at any given time, the stress on the structure as well as the stress on the humans. This is where one can really see the link between math and physics, and biology. Everything that has to do with physics, such as speed and acceleration, and biology, like the effects on the coaster on the body, must be documented, detailed and explained for the experts, before the foundation for the coaster gets poured in. All the laws and knowledge of other branches of science must be translated mathematically, and then the math makes sure it works. This is the very first step to building a coaster and is a very important one, because this is where you find out if your coaster is possible to build, and if it will be built.

The biology:

One area one would tend to forget to link coasters to would be biology. Biology is a very important part. After all, the goal of a coaster is make the human being “feel” the ride. The effects a coaster has on it’s passengers it what makes it good or bad. The main part of the emotion comes from the forces of gravity, or G forces. 1 G, or one G force, is the force that you would feel which is equivalent to what normal gravity feels like (9.81m/s2). As forces increase, a way to measure them is in Gs. Meaning if someone tells you that you would feel 3 Gs, that means you would feel 3 times the force of gravity and whatever direction. It also means that you feel 3 times as heavy as you are. Someone who is 100 pounds and goes in a low of a coaster and experiences a force of 3 Gs downwards, means that three times the force of gravity is pulling down. Now her mass is still 100 pounds, but she feels it’s like 300 pounds.

This is where biology comes into play. G forces can make a ride crazy and make you feel intense sensations, but it can also kill you. The maximal amount of Gs your body can withstand differs all the time due to many circumstances. A body can go up to about 9Gs before anything serious and permanent starts to happen. For coasters, the main concern is the time exposed to the forces. The longer the force is applied, the smaller it can be to do some wrong. A human will die after being exposed to 10 Gs for one minute [5]. The world record for the number of Gs withstood is 179.8 Gs!!![7]. He was in a car crash racing, so it was accidental, and suffered 29 fractures and 6 heart stoppages but nonetheless,he was exposed to that many amount of Gs and lived to talk about it.The ejector seat of a combat jet exposes the pilot to 16Gs[6], and the fighter pilot does not die. It all depends on the time exposed, and also, the condition of the human. A fit fighter pilot, who is trained to withstand up to 9 Gs, about the limit, can pass out at 2.5 is he is stressed![6]. If someone has a poor heart, he may not be able to withstand the forces he will be exposed to during a ride.

Keep in mind these are positive Gs. The threshold for negative Gs is way less, to the order of 2-3 negative Gs, and is called redout. This causes the eyes to become dangerously bloodshot [1].

In any case, when strong Gs are applied to your body, your organs also react to this newly applied force. Some organs are smashed together, and the blood flow is altercated. At 5 Gs, your feet veins’ pressure is multiplied by 5, and you retinal artery’s pressure is 0! [6] That’s why at high Gs, you lose color in your sight, and then sight altogether. Other things that can happen on a roller coaster are: passing out due to lack of blood in the brain, diminution or loss of eyesight, neck problems due to stress on muscles, and heart problems, ranging from irregular heartbeats, to increased pressure, even to stroke. [6] But there is no need to worry, as roller coasters never come close to those limits, as it would be too dangerous. The highest amount of forces by a roller coaster is 6.5 in Houston by the “Texas Tornado”. [6]In any case, there is danger, as there is in everything and they estimate that there is one death in 150 million. [6]

Another sector in which biology is important is motion sickness. Motion sickness occurs when a body is put through motions and forces and where sight is lost with a consistent reference point.[3] The balance center of the inner ear send commands to the brain, and in motion sickness cases, this information is different from that of the eyes, which causes you to feel sick. This is a lesser effect on the body due to roller coasters as the worst that can happens is to feel sick and maybe throw up.

This is where the link between biology and the physics and math come to life.The mathematical calculations and models, can predict if the human will be able to withstand the forces the physics of the coaster will expose the human body to. It is a marvellous coalition of biology, math and physics. People can think that there is no link between all the sciences, and that each science takes care of their own problems independently from others, but as you were able to see in this paper in the creation of roller coasters, all 3 sciences are needed. If only one of the three sciences disappear, there will be no more roller coasters on the face of this planet! In any case, it can only be gratifying to all scientists for everyone to realize that all sciences are needed, and great interdependencies create amazing results.

Works Cited

[1]L, John: Aerodynamics and G forces: G forces, visited March 16th, 2003.

[2]Harris, Tom: How Roller Coasters Work: Staying on track, visited March 16th, 2003.

[3]Barnas, Gary P., Motion Sickness: Prevention and Treatment, created 1997-12-09, revised 2002-06-12, visited March 16th, 2003.

[4]Encarta: Roller coaster, visited March 16th, 2003.

[5]NASA: Roundworms, Stronger Than Humans?, created January 23rd, 2003, visited March 16th, 2003.

[6] Crocq, Mathieu: Montagnes russes,Science & Vie, 1019pp.74-77, (2003)

([6] Main non-internet source)

[7]The Guinness book of world records 1997: Endurance: Highest g forces, p.60, (1996)