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Re: ENERGY WITHOUT W and Q



It seems to me that most recent disagreements come from
attempts to defend the First Law as dU=Q+W. Here is
how Feynman described this law without Q and W.

"There is a fact, or if you wish, a law, governing all natural
phenomena that are known to date. There is no known
exception to this law ? it is exact so far as we know. The
law is called the conservation of energy. It states that there
is a certain quantity, which we call energy, that does not
change in the manifold changes which nature undergoes.
That is the most abstract idea, because it is a mathematical
principle; it says that there is a numerical quantity which
does not change when something happens. It is not a
description of a mechanism, or anything concrete; it is
just a strange fact that we can calculate some number and
when we finish watching nature go through her tricks
and calculate the number again, it is the same."

What he is saying, in my interpretation, is that U, the sum
of all known forms of energies, remains constant. Some
components of the sum decrease while others increase
but U remains the same. That is the principle we use in
solving some physics problems. Why is this not enough
for the first course?

I do not know how introduce various forms of energy
without leaning on the concept of work (which is the
common logical denominator in most textbooks). And
I consider Q to be an essential concept, as outlined at:

http://alpha.montclair.edu/~kowalskiL/energy.html

Some corrections were made in the above during the
current debate. This is a draft of what I would like to
present or publish next summer. Please comment.
Ludwik Kowalski