There are many things that vary by this equation , including some found in the topics of fluids, heat, electricity and magnetism. For all the rest we treat fluids, heat, etc. separately. The above stuff is glopped together with a one equation fits all approach. Then teach it to others, and you will learn more than they do. Find why the curve ball curves.
Heat energy can do useful work.
Gauss's law , sort of. You will get a charge out of capacitors . Or go beyond series and parallel into circuit nirvana or hell, depending on your point of view. Know the units and you will automatically know a lot. Derivation of Biot-Savart law .