Further energy transformations

17/10/15
Updated by Siming

Here is some further research into energy transformations in a rollercoaster.

·     The ride often begins as a chain and motor (or other mechanical device) exerting a force on the train of cars to lift the train to the top of a hill.

·     Once the cars are lifted to the top of the hill, gravity takes over and the remainder of the ride is an experience in energy transformation.

·     At the top of the hill, the cars possess a large quantity of potential energy. The car's large quantity of potential energy is due to the fact that they are elevated to a large height above the ground.

·     As the cars descend the first drop they lose much of this potential energy in accord with their loss of height. The cars subsequently gain kinetic energy. The train of coaster cars speeds up as they lose height. Thus, their original potential energy (due to their large height) is transformed into kinetic energy (revealed by their high speeds).

·    As the ride continues, the train of cars are continuously losing and gaining height. Each gain in height corresponds to the loss of speed as kinetic energy (due to speed) is transformed into potential energy (due to height).

·    Each loss in height corresponds to a gain of speed as potential energy (due to height) is transformed into kinetic energy (due to speed). The transformation of mechanical energy changes from the form of potential to the form of kinetic and vice versa.

·     On a well designed roller coaster loop, the riders will not be able to sense when they are traveling upside down. This is done by making sure the force that is exerted on the rider is at least equal to the weight of the rider. Centripetal force applied to the track depends on the velocity of the car. In order to apply enough centripetal acceleration the roller coaster car has to either be traveling very fast or the radius of the loop has to be made small.

·    The underlying principle of all roller coasters is the law of conservation of energy, which describes how energy can neither be lost nor created; energy is only transferred from one form to another. The first hill of a roller coaster is always the highest point of the roller coaster because friction and drag immediately begin robbing the car of energy. At the top of the first hill, a car's energy is almost entirely gravitational potential energy.

·    The typical roller coaster works by gravity. There are no motors used to power it during the ride. Starting from rest, it simply descends down a steep hill, and converts the (stored) gravitational potential energy into kinetic energy, by gaining speed. A small amount of the energy is lost due to friction, which is why it's impossible for a roller coaster to return to its original height after the ride is over. 

·     On a well designed roller coaster loop, the riders will not be able to sense when they are traveling upside down. This is done by making sure the force that is exerted on the rider is at least equal to the weight of the rider. Centripetal force applied to the track depends on the velocity of the car. In order to apply enough centripetal acceleration the roller coaster car has to either be traveling very fast or the radius of the loop has to be made small.

·     The underlying principle of all roller coasters is the law of conservation of energy, which describes how energy can neither be lost nor created; energy is only transferred from one form to another. The first hill of a roller coaster is always the highest point of the roller coaster because friction and drag immediately begin robbing the car of energy. At the top of the first hill, a car's energy is almost entirely gravitational potential energy.

Bibliography:

Engineering K-PhD Program, Pratt School of Engineering, Duke University. Lesson: Physics of Roller Coasters. Last modified: November 4, 2015. https://www.teachengineering.org/view_lesson.php?url=collection/duk_/lessons/duk_rollercoaster_music_less/duk_rollercoaster_music_less.xml

Roller Coaster Physics. 2009 – 2015. http://www.real-world-physics-problems.com/roller-coaster-physics.html

Wayne, Tony. (1998) Coaster Physics: An Educational Guide to Rollercoaster Design and Physics for Teachers and Students