Energy of a Roller Coaster

In this animation, you see a Roller coaster car starting from the top of the first hill. Notice that this hill is the largest because in typical roller coasters, the total energy put into the system is equal all put in by the first hill. All the work is done by the chain and motor to lift the car to the top of that hill. So notice that the total energy ( on graph) is the same value as the amount of gravitational potential energy (GPE). There are several other important things to notice here:

• As the car starts to roll down the hill its kinetic energy (KE) starts to increase as the GPE decreases. The total energy, still equal to GPE + KE, remains constant through the trip.
• When the coaster is at the top of the second hill (about half the height of the first) half of the energy is in the form of GPE, the other in the form of KE.
• When the coaster has reached the bottom and is on a level surface the total energy is all in the form of KE.
• Whether the car is going up or down, the KE is a positive value because energy is a scalar quantity. It has no direction to it. Remember that energy is defined as the ability to do work and the work can be done in any direction.
• Upon striking the barrier at the end of the track notice that the total energy falls dramatically as energy is transferred from the cart into barrier (breaking it) and the air (as heat and sound).

This simulation is ignoring any effects of friction.

©1998 Science Joy Wagon