Re: Zero with units?

[Herbert H Gottlieb <herbgottlieb@JUNO.COM>]

On Sun, 19 Sep 2004 15:34:06 -0400 James Frysinger <frysingerj@COFC.EDU>
writes:
> I tell my students that zero is not nothing.

*** However, let us consider the situation where you are asked
a question such as , " How much are you willing to donate to Busch
for the upcoming election?"  Would you say "zero", or would you say
"zero dollars"?

Herb Gottlieb
> Quantities have dimensionality and "carry" units with them. Their
> value is a
> product of a number and those units. The unit for mass is the
> kilogram. Thus
> it is appropriate to say "this object has mass m = 0 kg" (where the
> "m" is in
> sloping type). One might say that, for example, of a photon.
>
> As the lead reviewer of new and revised IEEE standards for adherence
> to proper
> use of the SI and so forth, I would "ding" a standard that said
> something
> silly like
>         "the potential at this point is 0";
> it should be
>         "the potential at this point is 0 V".
> The same would occur with a statement about the resistance of a
> superconductor, so this is not a matter of scale or reference
> point.
>
> Though the magnitude (numerical value) of a quantity may go to zero,
> it
> retains its dimensionality and thus its units.
>
> Jim
>
> On Thursday 2004 September 16 14:33, leinoffs@SUNYACC.EDU wrote:
> > Hello,
> >
> > Sorry to join this discussion so late, but I get the digest
> version of
> > Phys-L (and don't read them until days later, even so).  I
> appologize if my
> > point has already been made
> >
> >
> > Did someone say:
> > "Since the number 0 doesn't need units for anything, why try to
> use them?"
> > I think that it is pretty important to include the units in
> stating the
> > value of a temperature, even if the value is zero (e.g. 0 degrees
> Celsius)
> > I don't think any of us would have it any other way.
> >
> > Obviously this is a problem with temperature (and any other
> quantities?)
> > since the value of zero on the Celsius and Fahrenheit scales are
> based on
> > an arbitrary temperature.  Those zero values of temperature do not
> coincide
> > and do not represent an "absolute" temperature value.
> >
> > Stu Leinoff
> > Adirondack Community College


Herb Gottlieb from New York City
A friendly  place to live and visit