The Concepts of Physics Involved in The Design and Working of Roller Coasters

Roller coasters are a staple for amusement parks around the world. They consist of a cart where people are ferried along a track, going up and down the selected route. Modern roller coasters have been made more thrilling for the riders by including bends along the tracks and even loops where the riders hang upside down.

Roller coasters have come a long way since the first commercial rollercoaster was constructed. The first roller coaster, The Switchback Railway that debuted at Coney Island on June 13, 1884 had a meagre top speed of 6mph. This is sharp contrast with modern roller coasters, the fastest of which is the Formula Rossa in Abu Dhabi which reaches a top speed of 149.1mph.

Roller coasters work on simple concepts of physics and their working and design depends on the laws of physics. This essay aims to show and explain the physics involved in the design and working of roller coasters.

The data used in this essay is mainly secondary data obtained from a number of online sources.

The roller coaster ride has various parts:

(a) The Ascent – the cart carrying the passengers rises up a tall hill so as to reach its initial position. In some kinds of rollercoasters, the passengers get onto the cart at this point after climbing a flight of stairs.

(b) The Descent – the cart quickly descends a slope carrying the passengers whom at this time experience a rush.

(c) Smaller hills and Bends – the cart zooms along the track manoeuvring bends both sharp and gentle to give the passengers an exhilarating feeling.

(d) The loop – the cart goes round a vertical loop where at the top, the passengers are upside down.

The laws of physics are always applied in the functioning of a roller coaster. First of all, the laws of physics are needed to lift the cart up the track to its initial position. The roller coaster is brought up the hill by an electric winch which winds the cars to the top of the first hill. The designers have to choose an appropriate rope which can provide sufficient tension needed to lift the cars.

The energy given to the cars however is not lost. The energy given to the cars from the electric winch is stored in the cars as Gravitational Potential Energy. The higher the winch winds the cars, the more Gravitational Potential Energy the cars would have (Chris Woodford, 2017). The designers of the roller coaster can therefore easily determine how much energy the roller coaster would have for the whole ride by using the equation: ΔUg = mgΔh where ∆Ug is the change is gravitational potential energy, m is the mass of the cart and people, g is the gravitational field attraction and ∆h is the change in height of the cart and people.

Once the passengers have boarded, the cars are allowed to descend. As the roller coaster descends, the gravitational potential energy is transformed into kinetic energy due to the motion of the roller coaster. Here the roller coasters apply the law of conservation of energy which states; in a closed system, the total energy of the system is conserved (Mark E. Tuckerman, 2011).

The lower the cars reach, the more potential energy is transformed into kinetic energy hence the higher the velocity since K = ½mv2. This then increases the velocity of the cars and thus increases the momentum of the cars since p = mv where p is the momentum of the system, m is the mass of the people and the cars and v is the velocity of the cars and the people. At the bottom of the lift hill, the train’s kinetic energy is at the highest point it’ll be on the track, enough to push it through the succession of smaller hills and turns.

The roller coaster can go over more hills due to this momentum. However, the hills cannot be higher than the initial hill. If it was higher than the initial hill, it would mean that the energy needed to climb this hill would be higher than the potential energy gained from the first hill. This would therefore cause an energy deficit since energy cannot be added to the system of the roller coaster. The cars would therefore rise to a height where there is sufficient energy and fall back down.

Modern roller coasters have introduced loops in the course of the rides. The loops seem to be gravity defying however, they follow the laws of physics. The loops in roller coasters are not circular in nature but rather have a shape geometrically known as clothoid.

The clothoid loop has a smaller radius at the top. The centripetal acceleration is defined as the product of the velocity squared divided by the radius of the moving body. The radius of the moving body is equivalent to the radius of the loop. A smaller radius at the top leads to a lower value of centripetal acceleration needed to complete the loop by the roller coaster therefore decreasing the acceleration to values low enough to provide a comfortable yet thrilling experience for the rider.

In conclusion, the laws and principles of physics are paramount in the design and function of roller coasters. If the engineers do not take them seriously, the effects can be catastrophic such as the Big Dipper Accident in London 1966 where one of the cables necessary for pulling the cars up the initial hill snapped thus sending the passengers rolling back and killing five children in the process (Rachael Bletchly, 2015).

The major law of physics used in roller coasters is the law of conservation of energy. The energy gained by the roller coaster is Gravitational Potential Energy. This energy is then transformed into Kinetic Energy once the cars begin to move. The roller coaster does not gain any additional external energy along the track and moves only because of the initial energy gained. Energy is however lost from the roller coaster due to friction and air resistance thus causing the roller coaster to finally come to a rest.

As time progresses, new methods developed aimed at reducing the amount of energy lost during the ride through friction and air resistance will give rise to even faster roller coasters that will go on for longer distances providing the riders a more wonderful and more comfortable experience.

Most roller coaster rides have also incorporated bends and turns into their courses. These also apply principles of physics such as dividing forces into their components. When negotiating bends, the roller coaster track is tilted towards the inside of the track. From this, the inward acting force is increased making the course easier to negotiate by using the lateral component of the normal reaction.