Let’s start with definitions. Potential energy is the total energy that could be used. Works well for gravity and chemical energy. I’m going to assume you’re working with gravity examples. Kinetic energy is the total energy you are using right now or up to this point with in the confines of your example.
Imagine a fuel gauge. The full (the ‘F’) represents the highest your object will be in your example. The empty (the ‘E’) represents the lowest your object will be in your example. The gauge arm is the height of your object. The area between arm and the ‘F’ is your potential energy, and the area between the arm and ‘E’ is your kinetic energy.
So, they never mix. One is converted into the other dependent on your object’s height.
MKDesign 