On Thu, 25 Sep 2003 01:16:33 GMT, Dave Shrader
wrote:



Gene Nygaard wrote:

[SNIP]


Apparently you are claiming that pounds are not units of mass.

Where did you learn that?

Well, I learned that a Pound is a unit of Force.
Well, I learned that a Slug [pound mass] is Pound*acceleration.
Well, I learned that mass is pound*sec^2/foot.

Where did I learn this? What's my source? Physics 101, University
Physics, Sears and Zemansky, Addison-Wesley Publishing, 1956, Chapter 6,
page 94.

I hope tou don't need another reference?

Now, what's your real problem? What are you trying to say?

Can you quote it to me, specifically where it says that pounds are not
units of mass? I'll bet you just misunderstood what it said. I have
the 1970 edition of Sears and Zemansky myself, so I'm betting that if
anything, what it actually says is clearer in that older edition than
it is in the 1970 edition.

Pounds force do exist, of course. What I'm asking you to show me is
not that, but rather that pounds are not units of mass.

Sears and Zemansky didn't lie about this in 1956. They might have
been dishonest and deceptive about it, not concerned enough about the
possibility that fools like you would misinterpret what they said or
actually encouraging such misinterpretation. But they didn't lie
about it. Some textbooks today might actually lie about it (or,
alternatively, their authors are too poorly educated to know any
better--take your choice).

Gene Nygaard

Dave, W1MCE



Being the skeptic that I am, how can I convince myself that that is
true? Is there some textbook, or something from some national
standards agency, that would help me verify this?

Gene Nygaard

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

Gene, thanks for the compliment in calling the Program Chief Engineer
of the USAF MX [Peacekeeper] Re-Entry System/Re-Entry Vehicle a fool.

It says a lot about you. I forgive you.

Dave, W1MCE
+ + +

Gene Nygaard wrote:
not concerned enough about the possibility that fools like you

On Thu, 25 Sep 2003 12:13:47 GMT, Dave Shrader
wrote:

Gene, thanks for the compliment in calling the Program Chief Engineer
of the USAF MX [Peacekeeper] Re-Entry System/Re-Entry Vehicle a fool.

It says a lot about you. I forgive you.

Gee, if I'd known you were so important, I'd really have taken you to
task for being too damn stupid to understand what you read in Sears
and Zemansky!

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

On Thu, 25 Sep 2003 12:13:47 GMT, Dave Shrader
wrote:

Gene, thanks for the compliment in calling the Program Chief Engineer
of the USAF MX [Peacekeeper] Re-Entry System/Re-Entry Vehicle a fool.

It says a lot about you. I forgive you.

Dave, W1MCE
+ + +

Gene Nygaard wrote:
not concerned enough about the possibility that fools like you

Since you aren't honest enough to tell us exactly what Sears and
Zemansky said in 1956, I'll tell everyone what they said in 1970. If
there are any significant differences, feel free to point them out.
This thing is, I know that Sears and Zemansky weren't going to lie
about this, because they grew up using poundals, which are by
definition the force which will accelerate a MASS of 1 lb at a rate of
1 ft/s².

Francis Weston Sears and Mark W. Zemansky, University Physics,
Addison-Wesley, 4th ed., 1970.

[page 3]

1 pound mass = 1 lbm = 0.45359237 kg

[The actual number will, of course, be different in 1956, because the
U.S. didn't adopt this definition until 1959 (it had been in use in
Canada since 1953, six years before the international
redefinition).--GAN]

[page 4]

We select as a standard body the standard pound,
defined in section 1-2 as a certain fraction
(approximately 0.454) of a standard kilogram.

[page 59]

In setting up the mks and cgs systems, we first selected
units of mass and acceleration, and defined the unit of
force in terms of these. In the British engineering system,
we first select a unit of force (1 lb) and a unit of
acceleration (1 ft s^-2) and then define the unit of mass as
the mass of a body whose acceleration is 1 ft s^-2 when
the resultant force on the body is 1 lb.

end quote

Now, Sears and Zemansky might be incompetent for not allowing for the
fact that there are going to be people out there who are too blamed
stupid to understand that that adjectival phrase "British engineering"
has some meaning, and that it identifies one particular limited subset
of the British units. It's perhaps even understandable, because that
fact would be quite clear to anyone who, like them, had grown up using
poundals in a "British absolute" system of units.

However, that doesn't change the fact that you are in fact one of the
people who are that stupid.

--
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

"Fundamentals of Physics", Haliday and Resnick, Second Edition, 1981

Appendix F, Conversion Factors

Mass

"Quantities in the colored areas [ounce, pound, ton] are not mass units
but are often used as such. When we write, for example 1 kg "=" 2.205
lb this means that a kilogram is a _mass_ that _weighs_ 2.205 pounds
under standard condition of gravity (g = 9.80665 m/s^2)."

The units dyne, Newton, pound, and poundal are listed elsewhere in
Appendix F as units of force.

73, AC6XG

Gene Nygaard wrote:

On Thu, 25 Sep 2003 12:13:47 GMT, Dave Shrader
wrote:

Gene, thanks for the compliment in calling the Program Chief Engineer
of the USAF MX [Peacekeeper] Re-Entry System/Re-Entry Vehicle a fool.

It says a lot about you. I forgive you.

Dave, W1MCE
+ + +

Gene Nygaard wrote:
not concerned enough about the possibility that fools like you

Since you aren't honest enough to tell us exactly what Sears and
Zemansky said in 1956, I'll tell everyone what they said in 1970. If
there are any significant differences, feel free to point them out.
This thing is, I know that Sears and Zemansky weren't going to lie
about this, because they grew up using poundals, which are by
definition the force which will accelerate a MASS of 1 lb at a rate of
1 ft/s².

Francis Weston Sears and Mark W. Zemansky, University Physics,
Addison-Wesley, 4th ed., 1970.

[page 3]

1 pound mass = 1 lbm = 0.45359237 kg

[The actual number will, of course, be different in 1956, because the
U.S. didn't adopt this definition until 1959 (it had been in use in
Canada since 1953, six years before the international
redefinition).--GAN]

[page 4]

We select as a standard body the standard pound,
defined in section 1-2 as a certain fraction
(approximately 0.454) of a standard kilogram.

[page 59]

In setting up the mks and cgs systems, we first selected
units of mass and acceleration, and defined the unit of
force in terms of these. In the British engineering system,
we first select a unit of force (1 lb) and a unit of
acceleration (1 ft s^-2) and then define the unit of mass as
the mass of a body whose acceleration is 1 ft s^-2 when
the resultant force on the body is 1 lb.

end quote

Now, Sears and Zemansky might be incompetent for not allowing for the
fact that there are going to be people out there who are too blamed
stupid to understand that that adjectival phrase "British engineering"
has some meaning, and that it identifies one particular limited subset
of the British units. It's perhaps even understandable, because that
fact would be quite clear to anyone who, like them, had grown up using
poundals in a "British absolute" system of units.

However, that doesn't change the fact that you are in fact one of the
people who are that stupid.

--
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

Jim Kelley wrote:
"Quantities in the colored areas [ounce, pound, ton] are not mass units
but are often used as such.

What is the mass of a banana slug in slugs?
--
73, Cecil, W5DXP

Cecil Moore wrote:

Jim Kelley wrote:
"Quantities in the colored areas [ounce, pound, ton] are not mass units
but are often used as such.

What is the mass of a banana slug in slugs?

Ask somebody at UC Santa Cruz. ;-)

73, ac6xg

On Thu, 25 Sep 2003 11:51:47 -0700, Jim Kelley
wrote:

"Fundamentals of Physics", Haliday and Resnick, Second Edition, 1981

Appendix F, Conversion Factors

Mass

"Quantities in the colored areas [ounce, pound, ton] are not mass units
but are often used as such. When we write, for example 1 kg "=" 2.205
lb this means that a kilogram is a _mass_ that _weighs_ 2.205 pounds
under standard condition of gravity (g = 9.80665 m/s^2)."

The units dyne, Newton, pound, and poundal are listed elsewhere in
Appendix F as units of force.

73, AC6XG

Apparently Halliday and Resnick were a lot smarter a couple of decades
earlier, when they were only a little past their prime:

Robert Resnick and David Halliday, Physics For Students of Science and
Engineering, John Wiley & Sons, 1960.

[page 10]

Legally, the pound is a unit of mass. But in engineering
practice the pound is treated as a unit of force or weight.
This has given rise to the terms pound-mass and pound-
force. The pound mass is a body of mass 0.45359237
kg; no standard block of metal is preserved as the pound-
mass, but like the yard it is defined in terms of the mks
standard. The pound-force is the force that gives a
standard pound an acceleration equal to the standard
acceleration of gravity, 32.1740 ft/sec².

So what are you going to believe? The main text of a book which
actually uses pounds? Or something hidden away in an appendix (which
the authors likely assinged some secretary to put together for them),
in a book which doesn't even use pounds?

Now go back in the book you have, and take a look at some of the
earlier stuff in it.

[page 356]

In the engineering system the unit of heat is the
British thermal unit (Btu), which is defined as the
heat necessary to raise the temperature of one
pound of water from 63 to 64°F.

How much water? You don't think that this is the amount of water that
exerts a certain amount of force due to gravity, do you?

What about when they give specific heat capacity in units expressed in
as Btu/lb °F in this book? What the hell do you suppose those units
in the denominator are? The corresponding metric unit in their book
are "cal/g°C"; does that give you any clues?

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

Gene Nygaard wrote:
Apparently Halliday and Resnick were a lot smarter a couple of decades
earlier, when they were only a little past their prime:

Hey Gene,

Maybe Halliday and Resnick in fact _avoided_ becoming "past their prime"
when they adapted their point of view to the one which now prevails.

73, Jim AC6XG

On Fri, 26 Sep 2003 10:05:08 -0700, Jim Kelley
wrote:



Gene Nygaard wrote:
Apparently Halliday and Resnick were a lot smarter a couple of decades
earlier, when they were only a little past their prime:

Hey Gene,

Maybe Halliday and Resnick in fact _avoided_ becoming "past their prime"
when they adapted their point of view to the one which now prevails.

It isn't a matter of "point of view." This isn't politics or an
opinion poll, and it isn't psychology or sociology, and it isn't
freshman literature. It's a matter of facts--of standards and
definitions. The fact is that pounds are units of mass, and that
pounds force also exist (a recent *******ization, of course).

Their 1981 Appendix misstates those facts. That's it, plain and
simple.

Now prevails? I issue you the same challenge I issued to our
Metrologist:

Show me an official definition of a pound force on the NIST pages.
Bet you can't do so. Note that a conditional definition, with a big
"if", indicating that this is only one possible acceptable definition,
is not sufficient--I want an official definition.

If you can't do that, try a broader problem: Show me an official
definition of a pound as a unit of force from ANY law of ANY country
in the world, or from ANY standard of ANY national or international
standards organization, or from ANY standard of ANY professional
organization.

Halliday and Resnick were right on top of things in 1960, already
aware of the change of definition that had taken place only 1 July of
the previous year, effective immediately on its publication. If you
haven't read what the National Bureau of Standards said in that
announcement, take the time now to do so (partial excerpt below).
http://www.ngs.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf
http://gssp.wva.net/html.common/refine.pdf

Announcement. Effective July 1, 1959, all calibrations in
the U.S. customary system of weights and measures carried
out by the National Bureau of Standards will continue to be
based upon metric measurement standards and except for
the U.S. Coast and Geodetic Survey as noted below, will be
made in terms of the following exact equivalences and
appropriate multiples and submultiples:
1 yard = 0.9144 meter
1 pound (avoirdupois) = 0.453 592 37 kilogram

Currently, the units defined by these same equivalences,
which have been designated as the International Yard and
the International Pound, respectively, will be used by the
National Standards Laboratories of Australia, Canada, New
Zealand, South Africa, and United Kingdom; thus there will
be brought about international accord on the yard and
pound by the English-speaking nations of the world, in
precise measurements involving these basic units.

Now, perhaps you think something changed between 1960 and 1981 when
the revised Halliday & Resnick came out. What would that have been?
Some change in the law? In the standards kept by the National Bureau
of Standards (later replaced by NIST)? Show me some justification for
a change, some change in facts, that would justify a different "point
of view" as you put it.

Or were Halliday and Resnick just terribly prescient, and they foresaw
some change that took place between 1981 and today? If so, tell us
exactly what that change was.

Or maybe you think that the 1959 redefinition is just some sort of
"legal definition" and that in the sciences we have some other "real
definition" that we go by. Is that your position? No problem if it
is, but if that is indeed what you are claiming, please fill us in on
a few followup questions:

1. What is the nature of the standard for a pound in its "scientific
definition"? Is it something mechanical, something electrical, or
what?

2. Who declared whatever the standard is to be the standard? NIST?
U.S. Congress? ISO? BIPM? The First International Extraordinary
Hydrographic Conference (they are the ones who defined the standard
for the international nautical mile)? Some other entity?

3. When was it made the standard? Just the year will do.

4. To whom does the standard apply? In other words, for whom does
the defining agency have the authority to make the standards?

5. Along the same lines, if this is a "scientific definition" which
differs from the "legal definition," what is its scope? What is "in
science"? Does it include Halliday and Resnick's definition of a Btu,
and their use of units of Btu/(lb °F) for specific heat capacity?
Same for Sears and Zemansky, the textbook cited by the Peacekeeper
Engineer?

6. What is the exact relationship between pounds force and the metric
units, or the relationship to the greatest precision in which it can
be expressed if it is not exact?

7. Even if all this were true, would it mean that the pound is a unit
of mass? Is there some rule that says that textbook authors are
allowed to bury their heads in the sand, and ignore the real world
which does in fact use the definition agreed on by those six national
standards laboratories of some of the most advanced nations in the
world in 1959?


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