When you walk do you move from potency to act? When you move from one place to another, do you move from potency to act? What is the relation between potency and act and the question of potential energy and kinetic energy?
The fact that you have the potential, or capacity to walk, and then you walk, you are fulfilling that capacity to walk making it possible to cover distance. The fact that you can move from potency to act is in your nature. It is a sign of being created. We are born in this condition or state, that is why we advance in maturity, because we have the capacity to change our present state (by the way it is always changing, eg. cells are being replaced constantly, and there is always some kind of movement taking place in our bodies, if not, we are dead.) But we do not move ourselves, this ability to move from potency to act is produced by God, just as we can make choices by our will. If we choose to move, we can, but we are not our own power. It’s the way God created us. If we are moved, we are moved by another. If we could move on our own, that would mean that every capacity or potential we could experience we would experience because movement is always towards fulfilling our potentials. All our potentials would be fulfilled at once,and we would be God, who has no potentials but is Pure Act. This is why it’s said, God move others, but does not move Himself, because , in a manner of speaking, all His potentials are filled, so no need for movement, movement is always toward fulfilling potentials, There are material movement, locomotion, and there are spiritual movements, eg. moving from the state of ignorance to the state of knowing, or knowledge, it manifest the truth of potency and act in created things. the universe is created, so with it comes the state or condition of potency and act, the universe is always experiencing motion, and change.
Relationship between potential energy, and kinetic energy to my mind means eg. a battery has the potential to produce electrical flow, but until it is hook up to an electrical device, it remains a potential, in other words, it has the capacity to supply the electricity needed by the device, (but is not in act, until a demand is made on it to supply the electron flow)
Kinetic energy is movement passed on to another object by contact eg. a billiard ball on a pool table hits another ball and so on until resistance stops it from moving. Everything mentioned has a capacity to move (potency) to moving (act) and it is always for a purpose. God is the Prime mover and He passes this movement on to secondary causes, kinetic energy, and potential energy, for examples.