Energy Transformation on a Roller Coaster

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  • Part of the physics of a roller coaster is the physics of work and energy. The ride often begins as a chain and motor (or other mechanical device) exerts a force on the train of cars to lift the train to the top of a vary tall 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.

  • Potential energy- the energy of vertical position (dependent upon the mass of the object)
  • 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.
  • Kinetic energy (energy of motion) is dependent upon the mass of the object and the speed of the object.
  • The train of coaster cars speeds up as they lose height. Then 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)


Transformation of mechanical energy from the form of potential to the form of kinetic and vice versa

Once a roller coaster has reached its initial summit and begins its descent through loops, turns and smaller hills, the only forces acting upon the coaster cars are the force of gravity, the normal force and dissipative forces such as air resistance
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•The force of gravity is an internal force and thus any work done by it doesn’t change the total mechanical energy of the train of cars.
•The normal force of the track pushing up on the cars is an external force. However, it is at all times directed perpendicular to the motion of the cars and is incapable of doing any work upon the train of cars.
•Finally, the air resistance force is capable of doing work upon the cars draining a small amount of energy from the total mechanical energy which the cars possess. However, due to the complexity of this force and its small contribution to the large quantity of energy possessed by the cars, it is often neglected.