Energy
Energy, in a common usage, is considered as an entity that empowers things to work. For example, in a sci-fi movie, a robot needs energy to move and talk. This can be done by charging it up or doing something similar to provide it energy. In physics(and sciences in general), the concept of energy somewhat deviates from this but the general principle is actually quite similar but also quite different. Energy in physics can be defined as a scalar quantity that must be applied to an object in order to either heat it up or do work on it. Energy is defined in the SI unit of Joules(J).
Think of it like this. Let's say you're out for a morning jog. You're moving with an energy known as kinetic energy, which is dependent on your speed. However, that energy had to come from somewhere. Well, that somewhere is your legs! Your leg muscles are performing work on the rest of your body. Admittedly, this may not be crystal clear to you until we cover work. So, if it's still confusing to you(which it should be if you need an introduction), you should head over to the page for work.
Here are the topics for this unit: