Roger Halstead wrote in message . ..
On Sat, 27 Sep 2003 11:48:24 GMT, Dave Shrader
wrote:

I am 240 pounds 'mass' on earth. That's a fact.
No, in the US system of measurement your mass is measured in slugs.
your weigh is measured in pounds and is 240# on earth

In the metric system mass is in kg. Again the metric system is easier.
240#=109.091 kg

If you expect to sound like you have some expertise in this area, I
suggest you study up on precision, on significant digits and the like.

You can't start with a mass with only 2 or 3 at the most significant
digits, and get a conversion accurate to 6 significant digits.

Furthermore, if he were 240.000 lb, then he would be 108.862 kg, not
109.091 kg. You also cannot use a conversion factor with only 2 or 3
significant digits, and get a result with six significant digits (you
used 1 kg = 2.2 lb, whereas the actual definition of a pound is
exactly 0.45359237 kg).


I am 240 pounds 'mass' on moon. That's a weird assertion!

Your mass is still the same (109.091 kg), but your weight is
considerably less on the moon.

His mass is still the same, 240 lb, is every bit as true. What's this
bull**** about mixing together pounds and kilograms in a totally
confusing and stupid system of units? After all, your claim above was
that "in the US system of measurement your mass is measured in slugs"
so why aren't you using these units?

Yes, if his mass is 240 lb, you could also say that his mass is 7.5
slugs.

But by the same token, you could use one of the old non-SI metric
systems, and say that his mass is 11.1 hyls, in the system in which
the base units are the meter for length, the kilogram for force, and
the second for time.

But the existence of the hyl does not prove that kilograms are not
units of mass. By the same token, the existence of the slug does not
prove that pounds are not units of mass.

Each of those units, the slug and the hyl (aka the metric slug), exist
in only one particular subset of units, a subset which forms a
coherent system of units like SI, in which there is only one unit for
each different quantity and that unit is a unitary combination of the
base units.

The only system which uses slugs is normally identified as the English
(or British, this identifier being a matter of history and
derivation), or the U.S. (because it is also used here) "gravitational
foot-pound-second system of units." Your characterization of it as
"the U.S. system" is vague and misleading, overly broad. The only
system which has slugs excludes many of the units used in the United
States, such as pints and gallons and bushels and horsepower and Btu
and miles and ounces and psi.


If that assertion is true, who changed the density of the moon??

It has nothing to do with the assertion, but the mass of the moon is
less than the mass of the earth.

The mass of the Earth is in fact 81.3 times that of the earth's moon,
and you are right, it has absolutely nothing to do with what Dave
Shrader was talking about.

The mass of you and the earth sets what you weight on earth.
Your mass and the mass of the moon set what you weigh on the moon. The

No. Even accepting that you are using a force definition of the
ambiguous word weight (IOW, a definition nonstandard for the context
of body weight), there is one other factor that is also especially
important. After all, remember that I told you above that the mass of
the Earth is 81.3 times the mass of the moon. Do you think that the
force due to gravity that an object exerts on Earth will be 81.3 times
the force that the same object would exert on the moon? What do you
suppose that other important factor might be (hint--while the force
varies only linearly with mass, it varies in inverse proportion to the
square of this other factor).

mass of the moon is much less than that of earth so you weight much
less on the moon.

--
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
"It's not the things you don't know
what gets you into trouble.

"It's the things you do know
that just ain't so."
Will Rogers