« on: Yesterday at 05:31:28 »
Thx PmbPhy. You point out that defining something like energy is not easy. I couldn't agree more. But you don't give Feynman's definition of energy. In fact you say:In fact my page doesn't define energy. It just describes the concept. I should have pointed that out. Feynman doesn't define energy either.
Richard Feynman wrote 
It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. However, there are formulas for calculating some numerical quantity, and we add it all together it gives 28 - always the same number. It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.