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Old September 24th 03, 05:45 PM
Gene Nygaard
 
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On Sun, 17 Aug 2003 17:14:21 GMT, Richard Clark
wrote:

On Sun, 17 Aug 2003 13:56:11 GMT, tad danley
wrote:

Roy Lewallen wrote:


I've tried to point out on this thread that although the feedpoint
impedance is an impedance with the units of ohms, and the impedance of a
plane wave in free space also has the units of ohms, they're not the
same thing.



This may not be a good analogy, but Specific Impulse of rocket motors
helps me to remember that the 'units' of something have to be considered
in the context of what is being measured. Specific impulse is a measure
of the performance of a rocket motor. It measures the thrust obtained
from a single kilogram of propellant burned in one second. The 'units'
of Specific Impulse are seconds, but we're not measuring 'time'.

73,


Hi Tad,

Your point is well taken. ALL physical phenomenon can be expressed
through a chain of conversions in the MKS system of units. When
someone tells you that their terminology is inconsistent between
disciplines (as such offered in this and other threads); it must then
be amenable to reduction to MKS terms or one of the two conflicting
expressions is invalid.

That is to say to the specific matter about the usage of "ohms:"
Here, the unit of ohm must be reduced to Meters, Kilograms, and
Seconds for both usages (electrical and radiative). At that point,
both will have a common basis for comparison and if in fact their
reduced terms are identical, then their common usage is also
identical.

One simple example is with the measurement of body weight on the
bathroom scale (a torsion or compression device) as opposed to the
weight measured on the doctor's scale (a beam balance). Let's say
before you go to the doctor's, you weigh yourself in around 165
pounds. When you arrive at the doctor's, his scale says you weigh
around 75 kilograms.

Let's remove this same scenario to the moon (you live in one of those
futuristic 1990's colonies forecast by the space race back in the
60's). Before you went to the doctor's you weighed in around 33
pounds. When you arrive at the doctor's, his scale says you weigh
around 75 kilograms.

Here we find the expression "pounds" suffers what appears to be the
same plight of "ohms" in that the determination of a value is
inconsistent. You may also note constants of proportionality on earth
and the moon. These constants when expressed as a ratio also describe
the significant differences between the earth and the moon.

The problem is that the term "weight" has a hidden association to the
constant of Gravity. The expression Gram is one of Mass, not weight.
The expression pound is not an expression of Mass unless you expand it
to include the term for the particular constant of Gravity. Mass is
constant in the Newtonian Universe, and weight is not.

If you were to have reduced the pounds to the MKS system both times,
you would have found it consistent both times (here on earth, and on
the moon).


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

Where did you learn that?

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
  #72   Report Post  
Old September 24th 03, 05:46 PM
Gene Nygaard
 
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On Sun, 17 Aug 2003 13:56:11 GMT, tad danley
wrote:

Roy Lewallen wrote:


I've tried to point out on this thread that although the feedpoint
impedance is an impedance with the units of ohms, and the impedance of a
plane wave in free space also has the units of ohms, they're not the
same thing.



This may not be a good analogy, but Specific Impulse of rocket motors
helps me to remember that the 'units' of something have to be considered
in the context of what is being measured. Specific impulse is a measure
of the performance of a rocket motor. It measures the thrust obtained
from a single kilogram of propellant burned in one second. The 'units'
of Specific Impulse are seconds, but we're not measuring 'time'.


It is a bad analogy--for the simple fact that in SI, the proper units
of specific impulse are newton seconds per kilogram (N·s/kg), or the
equivalent meters per second (m/s).

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
  #73   Report Post  
Old September 24th 03, 06:23 PM
Richard Clark
 
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On Wed, 24 Sep 2003 16:45:38 GMT, Gene Nygaard
wrote:


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

Where did you learn that?

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


Hi Gene,

Exactly. Perhaps you should re-consider the simple illustration of
difference that I offered in the post you responded to.

Does the weight you measure on a bathroom scale change from the earth
to the moon because your mass changed too? Jenny Craig would have an
armada of shuttles warming up in Florida to a steady trade if that
were true.

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html

The link:
http://physics.nist.gov/cuu/Units/units.html
is quite specific to the matter.

One of the supreme ironies comes in the form of the unstated
conditional. In your regard, it is pounds is intimately tied to the
gravitational constant (mass and G). In other regards SWR is
intimately tied to the source Z (always equal to the transmission line
characteristic Z, unless stated otherwise).

73's
Richard Clark, KB7QHC
  #74   Report Post  
Old September 24th 03, 06:41 PM
Dave Shrader
 
Posts: n/a
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I weigh approximately 40# on the moon!!! Too skinny for my height 5"9".

I better stay here. But my doctor wants me to loose 40#. Something's
wrong. I need a Twinkie!!

DD

Richard Clark wrote:

On Wed, 24 Sep 2003 16:45:38 GMT, Gene Nygaard
wrote:


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

Where did you learn that?

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



Hi Gene,

Exactly. Perhaps you should re-consider the simple illustration of
difference that I offered in the post you responded to.

Does the weight you measure on a bathroom scale change from the earth
to the moon because your mass changed too? Jenny Craig would have an
armada of shuttles warming up in Florida to a steady trade if that
were true.

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html

The link:
http://physics.nist.gov/cuu/Units/units.html
is quite specific to the matter.

One of the supreme ironies comes in the form of the unstated
conditional. In your regard, it is pounds is intimately tied to the
gravitational constant (mass and G). In other regards SWR is
intimately tied to the source Z (always equal to the transmission line
characteristic Z, unless stated otherwise).

73's
Richard Clark, KB7QHC


  #75   Report Post  
Old September 24th 03, 06:58 PM
Richard Clark
 
Posts: n/a
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On Wed, 24 Sep 2003 17:41:18 GMT, Dave Shrader
wrote:

I weigh approximately 40# on the moon!!! Too skinny for my height 5"9".

I better stay here. But my doctor wants me to loose 40#. Something's
wrong. I need a Twinkie!!

DD


Hi OM,

If you huff down a package of Ex-Lax you would take care of the
doctor's advice with a lot of "loose" weight. (Language is fun ;-)

73's
Richard Clark, KB7QHC


  #76   Report Post  
Old September 24th 03, 07:22 PM
Gene Nygaard
 
Posts: n/a
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On Wed, 24 Sep 2003 17:23:12 GMT, Richard Clark
wrote:

On Wed, 24 Sep 2003 16:45:38 GMT, Gene Nygaard
wrote:


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

Where did you learn that?

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


Hi Gene,

Exactly. Perhaps you should re-consider the simple illustration of
difference that I offered in the post you responded to.

Does the weight you measure on a bathroom scale change from the earth
to the moon because your mass changed too? Jenny Craig would have an
armada of shuttles warming up in Florida to a steady trade if that
were true.


So what happens when you get serious about your weight and go to the
doctors office or the gym and weigh yourself on one of those platform
type beam balances?

Would your pounds be different on the moon? By how much?

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html


There is absolutely nothing about pounds on this page. So don't be
bull****ting us.

The link:

is quite specific to the matter.


Not a link directly on the page above; maybe on one of the links
there.

There is absolutely nothing about pounds on this page either. You are
still bull****tiing.

One of the supreme ironies comes in the form of the unstated
conditional. In your regard, it is pounds is intimately tied to the
gravitational constant (mass and G).


They are? I asked you for some citation proving that pounds are not
units of mass. You have not done so.

--
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
  #77   Report Post  
Old September 24th 03, 08:54 PM
Richard Clark
 
Posts: n/a
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On Wed, 24 Sep 2003 18:22:24 GMT, Gene Nygaard
wrote:

On Wed, 24 Sep 2003 17:23:12 GMT, Richard Clark
wrote:

On Wed, 24 Sep 2003 16:45:38 GMT, Gene Nygaard
wrote:

So what happens when you get serious about your weight and go to the
doctors office or the gym and weigh yourself on one of those platform
type beam balances?

Would your pounds be different on the moon? By how much?


A balance, by implicit definition again, consists of comparing two
masses under the influence of Gravity. Given it is a bridge, in a
sense, the constant of Gravity is discarded from both sides and mass
is compared only. It is a convenience of earthly expectations (and a
defunct system of measurement) that the scale is marked in pounds.

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html


There is absolutely nothing about pounds on this page. So don't be
bull****ting us.


That is the whole point. You don't see pounds there for mass do you?
That's because pounds are not a unit of mass. They are a unit of
weight which is NOT a constant throughout the universe (nor on earth
for that matter).

The link:

is quite specific to the matter.


Not a link directly on the page above; maybe on one of the links
there.

There is absolutely nothing about pounds on this page either. You are
still bull****tiing.


Have you tried loosing weight?

One of the supreme ironies comes in the form of the unstated
conditional. In your regard, it is pounds is intimately tied to the
gravitational constant (mass and G).


They are? I asked you for some citation proving that pounds are not
units of mass. You have not done so.


Uh-huh. In equal measure, I couldn't "prove" that sparrows' tongues
are also "not" units of mass. Well, there are many here who's minds I
cannot change, you simply have to go to the end of that line. ;-)

73's
Richard Clark, KB7QHC

  #78   Report Post  
Old September 24th 03, 09:15 PM
Gene Nygaard
 
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On Wed, 24 Sep 2003 19:54:06 GMT, Richard Clark
wrote:

On Wed, 24 Sep 2003 18:22:24 GMT, Gene Nygaard
wrote:

On Wed, 24 Sep 2003 17:23:12 GMT, Richard Clark
wrote:

On Wed, 24 Sep 2003 16:45:38 GMT, Gene Nygaard
wrote:

So what happens when you get serious about your weight and go to the
doctors office or the gym and weigh yourself on one of those platform
type beam balances?

Would your pounds be different on the moon? By how much?


A balance, by implicit definition again, consists of comparing two
masses under the influence of Gravity. Given it is a bridge, in a
sense, the constant of Gravity is discarded from both sides and mass
is compared only. It is a convenience of earthly expectations (and a
defunct system of measurement) that the scale is marked in pounds.


The matter of convenience is in the other direction, stupid; we're
willing to substitute cheapness for accuracy in what we want to
measure on those unreliable bathroom scales. They aren't any more
accurate for measuring force than they are for measuring mass on
Earth; haven't you ever weighed yourself on your mother's scale or
somewhere else and found it differed from yours at home by several
pounds? Do you automatically assume you've gained or lost that much
weight.

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html


There is absolutely nothing about pounds on this page. So don't be
bull****ting us.


That is the whole point. You don't see pounds there for mass do you?


I don't see pounds as units of mass because this page just lists units
in the International System of Units.
http://w0rli.home.att.net/youare.swf

Show me something from NIST saying that pounds are not units of mass.
Or from some textbook.

That's because pounds are not a unit of mass. They are a unit of
weight which is NOT a constant throughout the universe (nor on earth
for that matter).


Just your say-so? That's the best you can do?

The link:

is quite specific to the matter.


Not a link directly on the page above; maybe on one of the links
there.

There is absolutely nothing about pounds on this page either. You are
still bull****tiing.


Have you tried loosing weight?


To quote a sge (you know who he is) in this newsgroup:

If you huff down a package of Ex-Lax you would take
care of the doctor's advice with a lot of "loose" weight.
(Language is fun ;-)

One of the supreme ironies comes in the form of the unstated
conditional. In your regard, it is pounds is intimately tied to the
gravitational constant (mass and G).


They are? I asked you for some citation proving that pounds are not
units of mass. You have not done so.


Uh-huh. In equal measure, I couldn't "prove" that sparrows' tongues
are also "not" units of mass. Well, there are many here who's minds I
cannot change, you simply have to go to the end of that line. ;-)


I can, OTOH, prove that pounds are indeed units of mass.

That will prove that you are flat-out wrong in your claim that they
are not.

Just for practice, consider the troy system of weights. Unlike their
avoirdupois cousins, and unlike grams and kilograms, the troy units of
weight have never spawned units of force of the same name. They are
always units of mass; a troy ounce is exactly 31.1034768 grams, by
definition. There is not and never has been any troy pound force or
troy ounce force.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
  #79   Report Post  
Old September 24th 03, 10:04 PM
Richard Clark
 
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On Wed, 24 Sep 2003 20:15:51 GMT, Gene Nygaard
wrote:


A balance, by implicit definition again, consists of comparing two
masses under the influence of Gravity. Given it is a bridge, in a
sense, the constant of Gravity is discarded from both sides and mass
is compared only. It is a convenience of earthly expectations (and a
defunct system of measurement) that the scale is marked in pounds.


The matter of convenience is in the other direction, stupid; we're
willing to substitute cheapness for accuracy in what we want to
measure on those unreliable bathroom scales. They aren't any more
accurate for measuring force than they are for measuring mass on
Earth; haven't you ever weighed yourself on your mother's scale or
somewhere else and found it differed from yours at home by several
pounds? Do you automatically assume you've gained or lost that much
weight.


I've nowhere introduced the topic of accuracy. It has nothing to do
with your original query. Weight and mass can both be measured to
considerable accuracy. It all depends on method and standards.

A bathroom scale is not a balance. A balance has a scale (the marks
along which the balance weights are moved and the markings upon those
same weights).

However, you do ask for a reference and acknowledge the NIST as a
reputable source (many here ignore this commonplace):
http://physics.nist.gov/PhysRefData/...constants.html

There is absolutely nothing about pounds on this page. So don't be
bull****ting us.


That is the whole point. You don't see pounds there for mass do you?


I don't see pounds as units of mass because this page just lists units
in the International System of Units.


Exactly.

Show me something from NIST saying that pounds are not units of mass.
Or from some textbook.

That's because pounds are not a unit of mass. They are a unit of
weight which is NOT a constant throughout the universe (nor on earth
for that matter).


Just your say-so? That's the best you can do?


I am a trained Metrologist. I have measured mass traceable to the
NIST. I have done this in four different Primary and Secondary
Standards Labs. I was the head Metrologist of two of them.

Have you tried loosing weight?


To quote a sge (you know who he is) in this newsgroup:

If you huff down a package of Ex-Lax you would take
care of the doctor's advice with a lot of "loose" weight.
(Language is fun ;-)


I suppose that is an affirmative.

I can, OTOH, prove that pounds are indeed units of mass.


By a reference found at the NIST? I think you would have done that by
now if you could.

That will prove that you are flat-out wrong in your claim that they
are not.


Well, I have seen a lot of math tossed over the transom here. But if
we are to work by your own standard, cite an NIST reference.

Just for practice, consider the troy system of weights. Unlike their
avoirdupois cousins, and unlike grams and kilograms, the troy units of
weight have never spawned units of force of the same name. They are
always units of mass; a troy ounce is exactly 31.1034768 grams, by
definition. There is not and never has been any troy pound force or
troy ounce force.


Hi Gene,

Sounds like you proved a pound is not mass.

The pages I offered provide a meaningful quote:
"The 3d CGPM (1901), in a declaration intended to end the
ambiguity in popular usage concerning the word "weight," confirmed
that:
The kilogram is the unit of mass..."

Any other usage of "weight" in regard to the sensation of the action
of Gravity upon an amount of mass is outdated by more than a century
of understanding and convention.

73's
Richard Clark, KB7QHC
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Old September 25th 03, 02:16 AM
Dave Shrader
 
Posts: n/a
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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?

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


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