Conservation of Mechanical Energy
If you look at the roller coasters, you can find something interesting. That’s right. There is no engine on the roller coaster. When we lift the roller coaster to the highest point, then the roller coaster moves by itself.
This is where mechanical energy conversion and conservation are applied. In other words, if you lift it to a very high point before you start, the roller coaster will have large potential energy. This roller coaster falls, and the potential energy is reduced. This reduced potential increases kinetic energy.
What is the fastest speed of a roller coaster? The fastest speed means the greatest kinetic energy. This also means that the potential energy is the smallest. In other words, the speed of the roller coaster will be the fastest when you are on the ground.
This is similar to Viking(Pirate ship) attraction. The Viking(Pirate ship) attraction has the highest end on both ends. And the fastest speed on the floor. At every point, kinetic energy and potential energy are complementary. After all, the total energy always remains the same.
However, in our world, mechanical energy conservation is hard to find. That’s because of the resistance and friction of the air. For example, consider raindrops falling from very high clouds. In the condition of no friction, raindrops can be terribly fast and may destroy buildings. Of course, that does not actually happen.