Today, we learned the changes of kinetic energy, potential energy, and total energy when a person is skating. The conclusions that we made include (assume friction is zero):
1) The kinetic energy is zero while the potential energy is maximum at the highest point. Inversely, the kinetic energy is maximum while the potential energy is zero at the lowest point.
2) As the object falls in gravity, kinetic energy increase while potential energy decreases; as the object travelling faster and faster, its kinetic energy increases while potential energy decreases.
3) The total energy remains the same for all of the above scenarios.
Now, we understanding that we can not create or destroy energy, but we can change its form. Something intrigued me is the relationship between this example and the motion of roller coasters. What are the conditions that the designers have to worry about in order to create a safe roller coaster? In addition, what would happen to gravitational potential energy if the object is moving horizontally? What about kinetic energy? Also, what would happen if we add friction to the skating track?