Re: [Phys-l] Work and Energy: which first?

[John Denker <jsd@av8n.com>]

Jeffrey Schnick wrote:

> > Maybe not a concrete tangible thing, but still a thing.
> > http://www.av8n.com/physics/reality-reductionism.htm
>
>
> I read your well-written document on reality vs. reductionism with
> interest.  Would you say that any real attribute/characteristic, such as
> mass and length, of anything is a thing?  Also, would you say that speed
> is a thing?

Several answers:

1) I accept rather expansive definitions of "thing".  I have it
on good authority that "the play's the thing ...."  So, yes, I
accept even abstract, intangible, non-conserved things such as
plays, speeds, etc. as _things_.

2) As for the speed thing in particular, I would probably try
to shift the student's attention away from that and toward the
associated momentum thing and/or the KE thing ... on the grounds
that the latter are more interesting things, since they obey
local conservation laws.

3) The important conceptual issue, IMHO, is not the thinginess
but the reality.  I am aware that the term "reality" means
different things to different people, and that it is distantly
related to the Latin word for "thing" (/res/).  In this context,
though, I use "real" as the antonym of "fictional", as discussed
in the document cited above.

Bottom line:  energy is a thing, it is real, it is locally conserved,
and it flows.

Speed is a thing, and is real in the sense of obeying strict physical
laws ... not including a conservation law.