[ausev] A Joule is a watt-second

[Steve Webb]

To Quote James Joule in 1845
" The mechanical power exerted in turning a magneto-electric machine
is *converted
into the heat* evolved by the passage of the currents of induction through
its coils; and, on the other hand, that the motive power of the
electro-magnetic engine is obtained at the expense of the heat due to the
chemical reactions of the battery by which it is worked."
Joule wrote this 20 years after the passing of James Watt, Allessandro
Volta, very close to the time that George Ohm and Andre Ampere Defined their
perspective Laws that define SI units.
The magic of electricity is that it is so well defined by mathmatics.

Steven Webb

On Mon, Jan 5, 2009 at 4:36 PM, Brian Lasseter <
blasseter.cmpe01 at gtalumni.org> wrote:

> On Mon, Jan 5, 2009 at 12:19 PM, Gil Dawson <Gil at gil.dawson.name> wrote:
> >  From http://www.batesville.k12.in.us/Physics/ANet/Science/Measure/
> > UnitsDictF2J.html
> >
> >> JOULE (J)
> >>     The SI unit of energy. One joule is the work done by 1 newton
> >> acting through a distance of 1 meter. One joule equals (1) 1 watt-
> >> second;...
> >
> > A rather odd coincidence, wouldn't you think?  They must've fudged
> > the whole SI system to make this work out.
>
> There is nothing coincidental or fudged in the SI system.  SI derived
> units are all defined in terms of SI base units and/or other SI
> derived units.  The watt happens to be defined in terms of joules (not
> volts or amps).
>
> - meter, kilogram, and second are SI base units.
> - The newton is the SI derived unit of force, equal to the amount of
> force required to give a mass of 1 kilogram an acceleration of 1 meter
> per second squared.
> - The joule is the derived unit of energy, equal to a force of 1
> newton traveling through a distance of 1 meter.
> - The watt is the SI derived unit of power, equal to 1 joule of energy
> per second.
>
>
> http://en.wikipedia.org/wiki/SI_base_unit
> http://en.wikipedia.org/wiki/SI_derived_unit
>
>
> --
> TTFN,
> Brian "Lasso" Lasseter
>
> "No Sane man will dance."   -Cicero (106-43 B.C.)
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