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Re: Energy before work



More I browse more I am impressed. I see that the
author thanks John Mallinckrodt, and many other
physicists for help.

The first is Unit C (conservation laws)
The second is Unit N (Newton Laws)
The third is Unit R (relativity)
The fourth is Unit E (electricity and magnetism)
The fifth is Unit Q (quantum aspects of physics)
The last is unit T (thermodynamics).

Ludwik Kowalski wrote:

I am browsing the Unit C of the "Six Ideas that Shaped
Physics" by Thomas A. Moore. The book (2nd edition)
was sent to me by the publisher (McGraw-Hill). I see that
the concept of energy is introduced, and used, long before
the introduction of work. On page 181 I see this:

"In physic, heat is any energy that crosses the boundary
between the two objects BECAUSE of the temperature
difference between them. Let me emphasize that to be
HEAT, the energy in question MUST:

1) Be flowing across some kind of boundary between
two objects, and
2) Do so as a direct result of a temperature difference
across that boundary.

We define work to be any OTHER kind of energy
flowing across the object's boundary. For example,
if I stir a cup of water vigorously and it gets warm
as a result, I have not "heated" the water, I have done
work on it; the mechanical energy that flows across the
water's boundary flows not because of a temperature
difference but because of my stirring effort. (Note
that work as defined here bears little conceptual
resemblance to k-work.)"

The concept of k-work was defined as "the amount
of energy that a particular interaction contributes
toward changing an object's kinetic energy." It is a
scalar whose value is negative when the interaction
reduces the object's kinetic energy (page 142).

The concept of energy is introduced on page 98,
after discussing the conservation of momentum.
Looks like a really innovating textbook. I suppose
some people already used the first edition. Was it
very different from what is above?
Ludwik Kowalski