There are generally two types of potential energies. One is gravitational potential energy, and the other one is elastic potential energy. But what is potential energy? Potential energy a a type of stored energy of position owned by the object. Just like a huge rock on the mountain top has the energy to fall once it has the chance to because it has potential energy.

The huge rock on the mountain top is an example of gravitational potential energy. But to be more precise, gravitational potential energy is the energy stored in an object as the result of its height /vertical position. We all know by common sense that the more damage the falling huge rock makes, the more energy it must have (to make such damage). So a rock with greater mass (heavier) will make a larger and deeper hole on the ground when it falls, and that means the greater the mass the oject has, the greater the gravitational potential energy will be. Also, if the rock falls from somewhere higher, the hole on the ground will be even deeper, and that means the higher the object is elevated, the more gravitational potential energy it can possess. And that is why we have the formula: Gravitation Potential Energy = mass * height * gravitational field strengh    (On Earth, the gravitational field strengh equals 9.8 N/kg)

How about elastic potential energy? Elastic potential energy is the energy stored in elastic materials as they are compressed or stretched. Imagine a spring is compressed. What will happen? It will bounce back. And iamgine a spring is stretched. What happen? It will restore its original shape. This is caused by elastic potential energy. And such a spring follows the Hooke's Law, which means that elastic potential energy is there only when the spring is either compressed or stretched, and the strengh of such potential energy can be expressed in this formula: Elastic Potential Energy = (1/2) * K (K is spring constant) * amount of compression/stretch.