Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: COLLISION 2

There is a conflict here. You have mentioned that putting a cup of water
in a microwave in some strict sense is not heating.
(Or perhaps it was someone else.)

If it was I, I misspoke.


>Remember that ALL heating (dE>0) is by doing WORK. What remains is the
>partitioning of that "work" into DQ and DW -- in cases where it
>matters. In the case of the piston/cylinder this is easy. For other
>processes this is NOT so easy.///

This seems to be the root of the concept:
that heating 'works' by doing work.

This is certainly not a casually arrived at position.

Oh no, it is not. It took years since the confusion of my graduate school
days, when it became clear that my professors didn't know what they were
talking about. I suggest that you spend a few minutes with my web page --
which is obviously still being developed. Although my views are not unique
to me, they are not likely to be found in a textbook.

But I cannot place it. It is not (I think) a model that
is often shared by engineers.

Engineers??? Good grief!!!! They learned their thermo from Carnot -- and
rarely even consider the Second Law. Only there does a correct
understanding matter -- and a correct partitioning of work into DW & DQ. I
do admire them for getting things done but not for their understanding of
physics.


These fellows see a 1 HP motor turning a bandsaw.
They see the work embodied in aluminum chips falling from the
sawn plate. They know - or think they know - that besides 740
watts of work, there is 740 watts of heating expended on the air
round the motor, on the warm (sometimes painfully hot) chips
and on the hot plate that remains to be sawn.
That motor paid back in work and heat 200%!

They contrast this with an electric element heater - it might
be rated at 750 watts - but all it can do is provide 750 watts
of warmed environment - no chips or other signs of progress!
All it could give was 100%

I am sure that this is much less than a respectable view.
What would you say?





brian whatcott <inet@intellisys.net>
Altus OK

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen