What is potential energy? A explanation of what energy is may help us understand better.
Examples of energy
A trampoline is a great example of potential energy. Basically, a trampoline uses springs.
When you jump on the trampoline, the springs are stretched. You could also say that the spring experienced a change in position.
While the springs are stretched, they store potential energy. This potential energy is then released as the springs compressed sending whoever jumped on it upward.
A special type of potential energy is gravitational potential energy. As the word gravitational suggests, this kind of energy will happen when you elevate objects against the earth gravity.
Example of gravitational potential energy
There is a ride at Bush Gardens in Tampa, Florida called Falcon's Fury.
The ride elevates people straight up to a certain height that is actually higher than the Statue of Liberty. Then, suddenly it drops them.
For the short period of time, may be a few seconds it keeps people in air, the ride has stored the highest gravitational potential energy for this height.
This gravitational potential energy is released when the ride drops everybody.
Recall that W = Fd
F is the force required to move the object upward. This force is equal to the weight of the object or mg.
d is the distance the object is moved.
Suppose we move this object to a height d = h.
Then, the gravitational potential energy = mgh
Just like work, energy is measured in Joules. This makes sense since
energy is the ability to produce work and work is measured in Joules.
It does not depends on the path you take as long as the vertical height is the same. The path could be vertical or slanted as shown below.
The only difference here is that the force required to move the rock on a slope is less than that required to move it straight up.
For the figure on the right the force is 50 N.
F = 300 J / 6 m = 50 N
However, for the figure on the left, the force is 100 N
F = 300 J / 3 m = 100 N