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.
