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wrote:

I am 240 pounds 'mass' on earth. That's a fact.

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

You've got me totally buffaloed now. I can't imagine what your
problem is.

Sure, mass is an ambiguous word, with several different meanings. But
there is only one of its meanings that is normally used with numbers
to express a measurement of its magnitude.

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

What in the world would the density of the moon have to do with your
mass?

It would be more understandable if you were having a hard time
understanding the normal definitions for this particular context of
the ambiguous word 'weight,' as it is quite properly and legitimately
used for body weight of humans in medicine (including space medicine
by NASA astronauts and doctors), and in sports, the normal reasons we
weigh ourselves, and in the science of anthropology as well. Or as
the word 'weight' is also used in zoology and veterinary medicine and
paleontology for the weight of other animals as well as humans. Now
certainly, in any of these contexts, this quantity will sometimes be
referred to as 'mass' as well; that is also quite proper and
legitimate.

My 'weight' is 230 pounds on earth. That's a fact.

My 'weight' would be 230 pounds on the earth's moon. That's also a
fact.

Let's review what I've already posted in other messages in this
thread, from ASTM

. . . thus, when one speaks of a person's weight,
the quantity referred to is mass. . . .

and from NIST

Thus the SI unit of the quantity weight used in this
sense is the kilogram (kg) and the verb "to weigh" means
"to determine the mass of" or "to have a mass of".

Examples: the child's weight is 23 kg

You know damn well that those kilograms are used for body weight all
around the world, including most hospitals in the United States. They
are indeed the proper SI units for this weight (which, as I pointed
out above, is also sometimes called "mass" instead). Furthermore, as
you've already seen many times over in the past few days, pounds are
by definition exactly 0.45359237 kg.
http://www.ngs.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf

THE REAL WORLD, AND THE REAL MOON

Now let's look at something different, not dealing with imaginary
transportations of you or me to the moon, but with the real world, and
the real moon.

What do you suppose it means when NASA tells us that the weight of the
Apollo 11 Lunar Module was "10,776.6 lbs" at the time of liftoff?

What ...

Whoops, just about forgot where I was and got ahead of myself,
forgetting that I need to slowly spell out what might be obvious to
people in other newsgroups. The Lunar Module at liftoff, of course,
was in actual fact located right ON THE MOON.

Now, what do you suppose those pounds are? If you really have no idea
how big the Lunar Module is and what its weight might be on the moon,
here's a big hint. NASA also tells us that the same Lunar Module at
the time of docking had a weight of 5738.0 lb.
Selected Mission Weights
http://history.nasa.gov/SP-4029/Apol...on_Weights.htm

Where was this LM at the time of docking? That's when it caught up
with the command module, where Commander Collins was at that time
"weightless" in an entirely different definition of the word weight,
in free-fall orbit around the moon. But not only was he not
weightless in the definition being used by NASA for this LM weight,
though he also was far from weightless in the definition of "weight"
as a force as used by Sears and Zemansky, from whom you claim to have
learned your physics. Much less in terms of force units than he would
have been on Earth (about a tenth as much, only an order of magnitude
guess), of course, but far from zero, in the Sears and Zemansky
definition of weight.

[Sears and Zemansky, 1970 page 61]
5.5 MASS AND WEIGHT
The weight of a body can now be defined more generally than
in the preceding chapters as the resultant gravitational force
exerted on the body by all other bodies in the universe. . . .

There is no general agreement among physicists as to the
precise definition of "weight." Some prefer to use this term
for a quantity we shall define later and call the "apparent
weight" or "relative weight." In the absence of a generally
accepted definition we shall continue to use the term as
defined above.

The NASA site discussed above, of course, is not some aberrant web
page. Nor is it some alteration of the units by the NASA public
affairs office--this is straight from the scientists and engineers.
This is indeed normal NASA usage, to call this "weight." It is also
normal NASA usage of the units "pounds." We even know that this is
exactly the term under which it was programmed into their onboard
computers, and the units used there as well, because we have dialogs
between Ground Control and the astronauts in which they are reading
out these figures for something called "weight" on both ends of the
conversation, and those weights are in pounds mass. You also
routinely see the same usage of the word weight when NASA talks about
the weight of the space shuttles or the weight of components of the
Space Station, or the weight of the spinning satellite some
spacewalkers wrestled into submission a few years ago..

As an aside, what do you think: Will NASA ever learn the lesson of
the Mars Climate Orbiter, and quite using pounds?

--
Gene Nygaard
At the present time, however, the metrical system
is the only system known that has the ghost of a
chance of being adopted universally by the world.
-- Alexander Graham Bell,1906

(Richard Harrison) wrote in message ...
Dave Shrader wrote:
"If that assertion (I am 240 pounds "mass" on earth. That`s a fact. I am
240 pounds "mass" on moon. That`s a weird assertion!) is true, who
changed te density of the moon??"

Mass is the bulk of matter though not necessarily equal to its weight. A
mass weighing 240 pounds on earth weighs less on the moon because there
is less mutual attraction between the moon, of much smaller mass than
the earth`s mass, and the object which weighs 240 pounds on the earth.

Mass is the property which provides a body with inertia. Mass is the
mechanical analogy of inductance. Mass is equal to the weight of a body
divided by the acceleration due from gravity (32ft./sec./sec.). This is
an expression of Newton`s 2nd law of motion: F = MA, thus M = F/A.

Newton`s 1st law says that to move a body at rest, enough force must be
applied to overcome its inertia.

Newton`s 3rd law says that for every action there is an equal and
opposite reaction.

The gravitational force of the earth is stated as "1".

Not really; the standard acceleration due to gravity (more accurately,
of free fall), or an approximation of the local acceleration, is
sometimes expressed as 1 lb/lbf, or 1 kgf/kg, or 1 gee. But it isn't
dimensionless, and it is also often expressed with units in which its
numerical value is not one (always, if you are using SI units, the
modern metric system).

The gravitational
force on the moon is about 0.16 that on earth, so an object weighing 240
pounds on earth would weigh only 38.4 pounds on the moon.

That's certainly true enough, at least for one definition of weight.
But it has nothing to do with Dave Shrader's "I am 240 pounds "mass"
on moon. That`s a weird assertion!" You are talking about something
different from mass.

Gene Nygaard

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

Gene Nygaard wrote:
"You are talking about something different from mass."

Yes. An orbiting astronaut may be weightless due to a particular balance
of forces, but he has mass and inertia.

We have weight and force. Either weight or force may be expressed in
pounds or kilograms. The conversion number I remember and use is: 2.2
pounds equal 1 kilogram.

The dictionary says the kilogram is a unit of mass, since a mass can
conveniently be accurately represented by an object. That particular
object is a cylinder of platinum-iridium alloy, called the international
prototype kilogram. This object is preserved in a vault at Sevres,
France.

Work may be meaasured as force times distance or as pounds times feet.
Power is work per unit time. Power may be expressed as foot-pounds per
minute. James Watt`s horse was said capable of working at a rate of
33,000 foot-pounds per minute. I calculate that as 250 kilogram-feet per
second or 76.2 kilogram-meters per second.

Best regards, Richard Harrison, KB5WZI

On Fri, 26 Sep 2003 22:20:17 GMT, Richard Clark
wrote:

On Fri, 26 Sep 2003 20:45:27 GMT, Gene Nygaard
wrote:
Not only did I prove Mr. Metrologist wrong, but I also proved that he
has no integrity.

Hi Gene,

And yet this does not seem to satisfy you. ;-)

No doubt this is product of an insecure basis in logic that is more
heartfelt than intuitive (despite the cut-and-paste philosophies).
snip

As I offered elsewhere; there are many in my fan club who's minds I
cannot change. For such trivial matters as yours, I am afraid you
have to go to the end of that line, and leave room for others of
substance ahead of you.

We've already heard the same lame excuse three times before.

Translation (from the point of view of Mr. Metrologist, aka R. Clark):

I already wasted three hours searching through the NIST web site for a
definition of a pound, and I couldn't find one either as a unit of
force or as a unit of mass. So I didn't figure that some
whippersnapper who just popped into this thread would be able to find
any official definition of the pound as a unit of mass there.

Okay, so he proved me wrong about pounds as units of mass. But I'll
be damned if he's going to get me admit that there isn't any official
definition of a pound force on NIST's pages.

end of translation

There, I told them anyway. BTW, though I can't find an "official"
definition of a pound force on NIST's pages, I can find a conditional
one, with a big "if" indicating fairly clearly that the pound force
has never been officially defined. Can anyone else even find that
one?

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

On Sun, 28 Sep 2003 13:44:48 GMT, Gene Nygaard
wrote:
We've already heard the same lame excuse three times before.

Hi Gene,

So how deep do I have to plant it before it takes root? ;-)

Like this compulsive interest with your fleas, you have written a
Gregorian Mass that consists of only one note. To your advantage, if
you had transposed "Old MacDonald Had a Farm"; then the monotonic
rendition would at least give the appearance of CW. You are
dreadfully out of your element here.

Given the low intellectual bandwidth offered by your specious claims,
I can sit back and enjoy some stylistic variations to exercise my
fingers at the keyboard. I especially enjoy your barnyard epithets -
such a self fulfilling cliche inspires my anecdotes. Here's another
that a liberal education would have exposed you to (if only):

21 Nov. 1667
"On this occasion Dr. Whistler told a pretty story related
by Muffett, a good author, of Dr. Cayus that built Key's
College: that being very old and lived only at that time upon
woman's milk, he, while he fed upon the milk of a angry
fretful woman, was so himself; and then being advised to
take of a good natured woman, he did become so, beyond the
common temper of his age."

Oh, if you missed the citation to the quote above, that was again from
Samuel Pepys (same day in fact) who, although not trained in the
sciences, did learn to respect others of learning and accomplishment.
And by the way, that earlier quote:
Dr, Wilkins saying that he hath read for him in his
church) that is poor and a debauched man, that the College have
hired for 20s. to have some of the blood of a Sheep let into his
body
Contains a Pound reference you obviously missed (from the exchange
rate of 20 Shillings). Now, as every good Englishman would have
understood back then, this was a conversion. If he held 20 coins they
were NOT a Pound which is a single coin. There is an equivalency, but
this does not constitute an equality. Pepys could have written 1£
that is shorter, but he did not as it was obviously not what was
tendered to the debauched man. Even the debauched man would
understand the significance of weight v. mass and how equivalencies of
1pound = umpty-ump grams does not render the term pound as mass,
merely an antiquated variant much like 10000 swallows' tongues = 1KG.
Shirley you don't consider swallows' tongues as units of mass? Cow
tongues (Neat's tongue to the English) perhaps. And this leads us
back to the good Dr. Cayus' condition - perhaps you should change your
diet.

The folks at the end of the line are beginning to complain - could you
move back some more?

73's
Richard Clark, KB7QHC

On Sun, 28 Sep 2003 18:04:26 GMT, Richard Clark
wrote:

Dr, Wilkins saying that he hath read for him in his
church) that is poor and a debauched man, that the College have
hired for 20s. to have some of the blood of a Sheep let into his
body
Contains a Pound reference you obviously missed (from the exchange
rate of 20 Shillings). Now, as every good Englishman would have
understood back then, this was a conversion. If he held 20 coins they
were NOT a Pound which is a single coin. There is an equivalency, but
this does not constitute an equality. Pepys could have written 1£
that is shorter, but he did not as it was obviously not what was
tendered to the debauched man.

Hi All,

The application of the monetary unit is not without is antecedents in
weight. The ancients, that is the pre-Newtonians, did not comprehend
the separable notion of mass from weight as they did not accept the
concept of "force" which was largely rejected by scientists of
Newton's day. In fact, Newton introduced the notion of forces in his
treatise "Opticks."

However, to return to the legacy of £. The symbol is drawn from
Libra. I have already discussed the operation of the balance scale
and its relationship to Libra is evident in the astrological
application. Libra (as is the latinate pondo) was the unit of weight
(not scientific mass, they had no such distinction) in ancient Rome.

I notice that our correspondent who relies on scientific cut-and-paste
retorts to dismiss scientific workers; and, as an acknowledged
untutored English speaker (several classes notwithstanding) also
leverages dictionaries to the same poor quality of transliteration.

The OED (which I am sure to get copious and unreliable rebuttal to)
offers of "mass" a physics application buried quite deeply within the
usage of this word across time (the OED is a dictionary of enumerated
usage by time, not by current application). For many hundreds of
years, mass merely meant the agglomeration of stuff (it didn't matter
what or why). Through the work of Newton's introduction of the
concept of force, the term, by OED account, then gained a distinction
such that they offer the definition:
"6.b. Physics. The quantity of matter which a body contains;
in strict use distinct from weight. 1704"

This is a pleasurable aside, these side bars of minutia to our usual
concerns. A do enjoy the drama queens that our group attracts and
the revisionist logic that attends their petty issues. Forgive me
Gene, but you don't have much else to offer and you will be gone soon
anyway, so go away mad (to invert an old saw). ;-)

73's
Richard Clark, KB7QHC

On Sun, 28 Sep 2003 02:02:54 -0500 (CDT),
(Richard Harrison) wrote:

Gene Nygaard wrote:
"You are talking about something different from mass."

Yes. An orbiting astronaut may be weightless due to a particular balance
of forces, but he has mass and inertia.

We have weight and force. Either weight or force may be expressed in
pounds or kilograms.

This is the only place you deal with Dave Shrader's comment.

The fact that you are implying he SHOULD NOT be surprised that his
mass on the moon would be 240 lb is totally obscured by the rest of
your ramblings.

The conversion number I remember and use is: 2.2
pounds equal 1 kilogram.

That will be acceptable for many purposes, iff

1. You are smarter than Roger Halstead and realize that you cannot
get six significant digits in your result by using this conversion
factor.

2. You are dealing with pounds in their normal definition as units of
mass, not pounds force.

You ought to be remembering both 1 lb = 453.6 g and 1 lbf = 4.448 N,
or something along those lines.

The dictionary says the kilogram is a unit of mass, since a mass can
conveniently be accurately represented by an object.

Of course, that applies to a troy pound standard as well (in the
United States from 1828 until at least after 1850, and probably until
1893 when the avoirdupois pound was redefined as an exact fraction of
a kilogram, our primary standard was a particular artifact known as
the Troy Pound of the Mint, and our avoirdupois pounds were units of
mass defined as an exact fraction of this standard).

That particular
object is a cylinder of platinum-iridium alloy, called the international
prototype kilogram. This object is preserved in a vault at Sevres,
France.

Work may be meaasured as force times distance or as pounds times feet.
Power is work per unit time. Power may be expressed as foot-pounds per
minute. James Watt`s horse was said capable of working at a rate of
33,000 foot-pounds per minute. I calculate that as 250 kilogram-feet per
second or 76.2 kilogram-meters per second.

Those aren't acceptable units in the modern metric system, however
(and it would actually be 76.0 kgf m/s, not 76.2).

BTW, Watt used the miner's measurements of mass as if they were
measurments of force in determining that a mine pony could do
sustained work at the rate of 22,000 foot-pounds per minute, before
using his arbitrary 1 horsepower = 1.5 ponypower conversion.

In the modern metric system, an English horsepower is 745.700 newton
meters per second, or 745.700 joules per second, or 745.700 watts.
Those pounds force convert to newtons, not to kilograms force, in SI.
The metric horsepower (PS in German acronym, CV in French acronym) is
75 kgf m/s, or 4500 kgf m/min. In SI, that's 735.4875 W.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

On Sun, 28 Sep 2003 18:04:26 GMT, Richard Clark
wrote:

Given the low intellectual bandwidth offered by your specious claims,

Still dreaming that somebody is going to come to your rescue, and show
us some NIST web page giving an _official_ definition of a pound as a
unit of force, aren't you?

Wake up and smell the coffee! It isn't going to happen, for several
reasons, including

1. Your research skills are better than those of most others
following this thread, and

2. You are better able to distinguish "swallow's tongue" conversion
factors from official definitions, and

3. They don't have a reputation to reconstruct, and

4. They don't know people at NIST that they can call on for help in
this search for the official definition, and

5. You've got them all convinced that you are an expert in this area,
and everyone expects that you could easily prove your point, and

6. A lot of people who know more about this than you do have
unsucessfully searched for an official definition, and

7. Dr. Barry Taylor, the NIST expert in this particular field who
must be a METROLOGIST if you are a mere capital-M Metrologist, is the
one who gives us the conditional definition which is a clear indicator
that an official definition does not exist.

Face the facts. Hard as it might be to believe (even for me, when I
first came to this realization!), THERE IS NO SUCH OFFICIAL DEFINITION
OF A POUND FORCE. Nobody has ever gone to the trouble of officially
defining these ******* offspring of pounds as units of mass, and
nobody will bother doing so in the future.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

On Sun, 28 Sep 2003 22:10:13 GMT, Gene Nygaard
wrote:
Wake up and smell the coffee!

Hi Gene,

You've missed one point (beyond I am not a coffee drinker) to which I
can respond:
I don't give a damn. :-)

Your condescending attitude towards others
all convinced that you are an expert
is obviously spun from your imagination as absolutely no one here has
commented for me, with me, to me, or about me (your QRM hardly allows
them that).

As for reputation.... You, admittedly, have absolutely no experience
in the matter, and this is not rec.sci.amateur.hour. Given your
petulance out of the gate discussing the subject, you don't even
qualify for honorary troll. You have no style, and the cut-and-paste
philosophy runs thick in this group as it is. Yours certainly is no
more distinctive, and when it is laid out by the ream like so much
textual fertilizer, it won't grow the crops to save the farm.

C'mon now Gene, we both know what I have to say on the matter is
wholly irrelevant to how you are going to boast about it around town.
Sort of like the tailor who wore on his belt "Killed seven with one
blow" and was only boasting about flies while gushing it up about
giants. Talk about (emphasis on talk) reputations made. ;-)

73's
Richard Clark, KB7QHC