Re: Energy before work" (was work done by friction)

[Leigh Palmer <palmer@SFU.CA>]

> I tried to start this thread several times (after being exposed
> to the idea of teaching energy before work at the modeling
> workshop in Arizona, years ago) but nobody responded.
> Is it possible, and desirable, to introduce the concept of
> energy before the concept of work? Leigh goes one step
> further, if I understand him correctly, and suggests the
> total elimination of the concept of work.

I didn't know that David Hestenes made this an important point
in his modeling. Needless to say, he is a very bright fellow,
and of course he would approach it that way. I can't imagine
how to do it otherwise. Hecht gets this right; he introduces
energy first.

No, I don't advocate abandoning the concept of work. I always
introduce energy before work, using Feynman's Chapter four as
the first item of business. I read the parable of Dennis and
his blocks to them in it entirety. Work is introduced later as
separate topic. I *never* touch what I consider to be a
damaging definition of energy as "the capacity to do work". I
consider it to be as odious as the definition of entropy as a
measure of the disorder of a system. Both definitions are, so
far as I understand the concepts, simply *wrong*.

The energy is a function of the state of a system.

Leigh