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units with zero?



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