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Re: Why work before energy in texts



"John S. Denker" wrote:

I stand by my assertion: Defining work in terms of potential
energy would be a blunder. Defining potential energy in
terms of work would be an even bigger blunder.

YES, work is defined as a dot product. But:

PEspr==work done against a spring (or -work by spring)
PEelctr==(later) is work against the electric field.
PEelctr==(later) is work against the electric field.

In general work done against a conservative force
BECOMES POTENTIAL ENERGY ASSOCIATED WITH THAT FORCE
(WITH RESPECT TO A CHOSEN REFERENCE LEVEL).

Why is this a "bigger blunder"? SORRY FOR ASKING IT AGAIN;
I REALLY WANT TO KNOW THE ANSWER. Note that I am not saying
that this textbook approach is the only one possible, or that
it is better than other approaches. But why is it a blunder?
Did I miss an explanation?
Ludwik Kowalski