2001-02-17
The so-called pound-mass vs. pound-force vs. pondual is so confusing, please
keep this confusion out of SI. SI is an absolute system. We don't need
units like kilogram-force when we have newtons. Don't waste your brain
energy trying to figure out what a kilogram-force weighs at sea level, on
the top of Mount Everest (8850 m) or on the planet Vulcan. Who cares?
When ever someone starts talking about kilogram-forces, introduce them to
the proper unit, the newton and explain there is no confusion between the
meanings and values of SI units no matter where they are. That also goes
for "other" non-SI units, whether they be old metric or old fart. Now,
there is a new name for FFU, OFU (old fart units). Remember, don't be a
metric farter, be metric smarter!
John
Keiner ist hoffnungsloser versklavt als derjenige, der irrtümlich glaubt
frei zu sein.
There are none more hopelessly enslaved then those who falsely believe they
re free!
Johann Wolfgang von Goethe (1749-1832)
----- Original Message -----
From: "Hooper, Bill and or Barbara" <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[EMAIL PROTECTED]>
Sent: Saturday, 2001-02-17 12:30
Subject: [USMA:11095] Re: Mass and Force
> I agree with gene (below). Explaining that a kilogram of mass and a
kilogram
> of force are "equal" is like stating that the temperature outside is equal
> to my speed if I am driving at 65 mph on a day when it is 65 degrees
> Fahrenheit (°F) outside. Does that mean 65 °F "equals" 65 mph?
>
> The kilogram of mass (the ONLY kilogram there is, in SI) is a totally
> different quantity from a kilogram of force (a very NON-SI unit that
should
> never be used in connection with SI measurents).
>
> An object has mass. It also has a force of gravity acting on it (usually).
> If the mass is measured in kilograms-mass and the force (a totally
different
> quantity) is measured in kilograms-force (a totally different unit), the
> fact that the two measurements may have the same number is irrelevant.
>
> (Also, it's not always true; it is only true when the gravitational field
is
> exactly equal to the arbitrarily adopted standard value. That's not
> precisely the case even at various points on the surface of the earth, and
> certainly is not correct anywhere else, except by purest coincidence.)
>
> The fact that the kilogram-force is defined in such a poor way (as the
force
> of gravity on a 1 kg mass) is one of the reasons why the kilogram-force is
a
> poor choice of unit to use for measuring weight or other forces.
>
> Regards,
> Bill Hooper
>
> ============
> Make It Simple!
> Make It Metric!
> ============
> > From: Gene Mechtly <[EMAIL PROTECTED]>
> > Subject: [USMA:11064] Re: Mass and Force
> >
> > On Fri, 16 Feb 2001, Joseph B. Reid wrote:
> >>
> >> ...at sea level at 45 degrees latitude kilogram-mass and kilogram-force
> >> are equal numerically by definition.
> > Joe,
> > If you are saying that 9.8 = 9.8, or 9.80665 = 9.80665, I must
> > agree that that is true there, or anywhere for that matter.
> > But I continue to object to the implication by your statement
> > that mass and force are somehow equal there or anywhere.
> > You are attempting to make sense of an incoherent mix of units
> > which is certainly *not* SI.
> > Gene.
>
>
