RV-7a baggage area
David Smith
I am strongly considering the RV-7a and am interested in knowing the
dimensions of the baggage area behind the seats.
Thanks
David
Dave S
EUTNET
RR Urban
> Thanks
>David
"EUTNET" wrote:
>>Baggage 100 lbs
+++++++++++++++++
ARRRGH.
Go directly to jail.
Do NOT pass GO.
Do NOT collect $200.
Monopoly BOb --
Dave S
MASS and VOLUME.
I feel your frustration.
And.. whats sad is.. the person who said 100 pounds probably thought
they were being helpful by pointing out something "obvious"
Dave
Russell Kent
> And hence we have ANOTHER person who cannot tell the difference between
> MASS and VOLUME.
>
> I feel your frustration.
>
> And.. whats sad is.. the person who said 100 pounds probably thought
> they were being helpful by pointing out something "obvious"
>
> Dave
Those that point out the mistakes of others would do well to mind their
own. Pounds (lbs.) are a measure of weight, not mass (which in the English
system would be slugs).
Van's own web page shows the baggage area to be "12+ cu. ft." If you need
a more precise number, I would suggest contacting Van's Aircraft directly.
http://www.vansaircraft.com/public/rv-7spe.htm
Russell Kent
Gene Nygaard
wrote:
>Dave S wrote:
>
>> And hence we have ANOTHER person who cannot tell the difference between
>> MASS and VOLUME.
>>
>> I feel your frustration.
>>
>> And.. whats sad is.. the person who said 100 pounds probably thought
>> they were being helpful by pointing out something "obvious"
>>
>> Dave
>
>Those that point out the mistakes of others would do well to mind their
>own.
Heed your own advice, fool.
>Pounds (lbs.) are a measure of weight, not mass (which in the English
>system would be slugs).
Where'd you get that idea?
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
Gentlemen of the jury, Chicolini here may look like an idiot,
and sound like an idiot, but don't let that fool you: He
really is an idiot.
Groucho Marx
Russell Kent
> Those that point out the mistakes of others would do well to mind their own.
Gene Nygaard responded:
> Heed your own advice, fool.
On entirely too many occasions I am indeed a fool, but I don't see where
devolving to name calling improves the conversation. Besides gently (IMHO)
chastising the intervening poster's rant, I still provided a useful answer to
the original poster's question (12+ cu. ft.) and a reference to the source.
Russell Kent continued:
> Pounds (lbs.) are a measure of weight, not mass (which in the English system
> would be slugs).
Gene Nygaard responded:
> Where'd you get that idea?
Uh, 2 years of high school physics (a jillion years ago). Perhaps a few web
references will help clear the cobwebs:
http://scienceworld.wolfram.com/physics/Slug.html
http://www.physics.ucla.edu/k-6connection/Mass,w,d.htm
Russell Kent
Russell Kent
Gene,
I see from your signature that this "weight vs. mass" thing is a personal windmill
for you. Fine. And I see that slug isn't used anymore (pound-force is the term
now). And for non-technical conversations, pound is a unit of mass.
Here's a question though: is this forum a technical or non-technical conversation?
And look at the sequence of postings: EUTNET wrote that the baggage area dimension
was 100 lbs, obviously meaning *weight*, and Dave S. complained that EUTNET
"cannot tell the difference between MASS and VOLUME." [emphasis Dave's] So I
believe Dave should have instead written "WEIGHT and VOLUME."
Now I suspect that Dave S. was merely careless and really does understand the
difference between mass and weight, and I was trying to gently pass along the
advice that newsgroup corrections are invariably inspected for even the slightest
error (see this thread!). I welcome you (Gene) jumping in at that point to
correct the whole weight vs. mass, slugs, pound-force hullabalu, but I wish you'd
do it with a bit less hostility. Someone may well have pissed in your cornflakes,
but I assure you it wasn't me. :-)
Russell Kent
Gene Nygaard
wrote:
>Russell Kent wrote:
>
>> Those that point out the mistakes of others would do well to mind their own.
>
>Gene Nygaard responded:
>
>> Heed your own advice, fool.
>
>On entirely too many occasions I am indeed a fool, but I don't see where
>devolving to name calling improves the conversation.
I see that even that wasn't enough to get your attention, Chicolini.
How big a bat do I need to hit you over the head with to get your
attention?
>Besides gently (IMHO)
>chastising the intervening poster's rant, I still provided a useful answer to
>the original poster's question (12+ cu. ft.) and a reference to the source.
Yes, you got that right. Too bad nobody will pat you on the back for
it, because you obscured it with irrelevant nonsense, and even worse,
an incorrect claim of error on someone else's part.
>Russell Kent continued:
>
>> Pounds (lbs.) are a measure of weight, not mass (which in the English system
>> would be slugs).
>
>Gene Nygaard responded:
>
>> Where'd you get that idea?
>
>Uh, 2 years of high school physics (a jillion years ago). Perhaps a few web
>references will help clear the cobwebs:
If you found those references, you also found many that got it right.
>
>http://scienceworld.wolfram.com/physics/Slug.html
Slugs are units of mass. That's not what I'm calling you on.
But that little-used 20th century invention, which didn't even appear
in physics textbooks before 1940, are by no stretch of the imagination
_the_ units of mass in "the English system."
Pounds force also exist, but that's also beside the point.
Back up your claim that pounds are not units of mass. That's where
you falsely claimed that Dave S. was making an error.
--
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
Russell Kent
> I see that even that wasn't enough to get your attention, Chicolini.
OK, you got me there. Haven't a clue who Chicolini is. Should I be insulted? Do
you now feel better having insulted me?
> How big a bat do I need to hit you over the head with to get your
> attention?
Clear, intelligent statements usually work.
> >Besides gently (IMHO)
> >chastising the intervening poster's rant, I still provided a useful answer to
> >the original poster's question (12+ cu. ft.) and a reference to the source.
>
> Yes, you got that right. Too bad nobody will pat you on the back for
> it,
(I don't care)
> because you obscured it with irrelevant nonsense,
Irrelevant? Wasn't to me. Nonsense? Um, nope.
> and even worse, an incorrect claim of error on someone else's part.
Perhaps.
> >Uh, 2 years of high school physics (a jillion years ago). Perhaps a few web
> >references will help clear the cobwebs:
>
> If you found those references, you also found many that got it right.
I just grabbed a few that looked to get to the point quickly.
> >http://scienceworld.wolfram.com/physics/Slug.html
>
> Slugs are units of mass. That's not what I'm calling you on.
It wasn't clear in your earlier hostile response.
> But that little-used 20th century invention, which didn't even appear
> in physics textbooks before 1940, are by no stretch of the imagination
> _the_ units of mass in "the English system."
I'm sorry, you're correct. I didn't mean to imply that they are the only unit of
mass. I was taught (perhaps incorrectly) that the unambiguous term for weight
(scientific meaning) in the English system was "slugs". Apparently it's also
"pounds force" now (it may have been them, too, and I've just forgotten it).
> Pounds force also exist, but that's also beside the point.
<sarcasm> Whew. Glad we're past that. </sarcasm>
> Back up your claim that pounds are not units of mass. That's where you falsely
> claimed that Dave S. was making an error.
Actually, I intended only to claim that Dave S. incorrectly stated mass when he
should have stated weight. From my perspective, the respondent about whom Dave S.
was complaining clearly intended "lbs" as a unit of weight.
The reference to the slug as the English mass unit was only intended as an offhand
remark. Pounds are units of mass in casual (non-technical) conversations, and
probably shorthand for "pounds force" in technical conversations.
For the record, I don't claim that slugs are the only unit of mass in the English
system, and I'm sorry to have inadvertantly made that implication.
Russell Kent
ET
> Back up your claim that pounds are not units of mass. That's where
> you falsely
>> claimed that Dave S. was making an error.
>
> Actually, I intended only to claim that Dave S. incorrectly stated
> mass when he should have stated weight. From my perspective, the
> respondent about whom Dave S. was complaining clearly intended "lbs"
> as a unit of weight.
>
Gene is correct, although mass and weight are equal in the same
environment (i.e. good ole earth gravity) so really correcting someone
on that is akin to correcting spelling mistakes on use-net.... kind of
useless.
Lbs IS a measure of mass (to us "common" folk) IFF acceleration is
either identified or implied. i.e. My mass is 195lbs at earth sea
level. Most people would say then mass = weight and weight = mass.
BUT I would say most of us have had experience where that is not true.
If you've traveled on an airplane... or ... perhaps flown one <grin>,
the acceleration factor has been at least momentarily increased or
decreased... with maneuvering... so even though you weigh 200lbs before
the you stepped into the plane, when you banked into that 30 degree
turn, you probably weighed something like 250+, but your mass never
changed.... When I took physics, mass was measured in a.u.'s & I have
no idea what the a stands for, and I think the u just meant "unit"
Although I beleive the correction was a bit petty... The hostle response
was a bit uncalled for, especially since Gene was correct.
Here is a good link that explains:
http://www.nyu.edu/pages/mathmol/textbook/weightvmass.html
ET >:)
"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams
Fred the Red Shirt
>
>
> I'm sorry, you're correct. I didn't mean to imply that they are the only unit of
> mass. I was taught (perhaps incorrectly) that the unambiguous term for weight
> (scientific meaning) in the English system was "slugs". Apparently it's also
> "pounds force" now (it may have been them, too, and I've just forgotten it).
I think you mistyped. 'Slugs' are unambiguously a unit of mass.
Pounds are ambiguously a unit of force. Ambiguity exists because it
is popular in some disciplines to use a unit of mass defined (loosely)
as that mass which weighs one pound.
But you knew that.
--
FF
Gene Nygaard
wrote:
>Gene Nygaard wrote:
>
>> I see that even that wasn't enough to get your attention, Chicolini.
>
>OK, you got me there. Haven't a clue who Chicolini is. Should I be insulted? Do
>you now feel better having insulted me?
Doesn't cost you any more to pay attention. It's from the Groucho
Marx quote.
>> How big a bat do I need to hit you over the head with to get your
>> attention?
>
>Clear, intelligent statements usually work.
I know better from long experience. If I hadn't clubbed you over the
head, you still wouldn't have looked into it enough to learn the
significant amount you have already learned, to be singing a
different tune now.
Still wrong, of course, but a totally different tune nonetheless.
>> >Besides gently (IMHO)
>> >chastising the intervening poster's rant, I still provided a useful answer to
>> >the original poster's question (12+ cu. ft.) and a reference to the source.
>>
>> Yes, you got that right. Too bad nobody will pat you on the back for
>> it,
>
>(I don't care)
>
>> because you obscured it with irrelevant nonsense,
>
>Irrelevant? Wasn't to me. Nonsense? Um, nope.
>
>> and even worse, an incorrect claim of error on someone else's part.
>
>Perhaps.
>
>> >Uh, 2 years of high school physics (a jillion years ago). Perhaps a few web
>> >references will help clear the cobwebs:
>>
>> If you found those references, you also found many that got it right.
>
>I just grabbed a few that looked to get to the point quickly.
>
>> >http://scienceworld.wolfram.com/physics/Slug.html
>>
>> Slugs are units of mass. That's not what I'm calling you on.
>
>It wasn't clear in your earlier hostile response.
>
>> But that little-used 20th century invention, which didn't even appear
>> in physics textbooks before 1940, are by no stretch of the imagination
>> _the_ units of mass in "the English system."
>
>I'm sorry, you're correct. I didn't mean to imply that they are the only unit of
>mass. I was taught (perhaps incorrectly) that the unambiguous term for weight
>(scientific meaning) in the English system was "slugs".
Must have been an overload of new learning, making you mistakenly
express what you thought you knew before.
>Apparently it's also
>"pounds force" now (it may have been them, too, and I've just forgotten it).
>> Pounds force also exist, but that's also beside the point.
>
><sarcasm> Whew. Glad we're past that. </sarcasm>
>
>> Back up your claim that pounds are not units of mass. That's where you falsely
>> claimed that Dave S. was making an error.
>
>Actually, I intended only to claim that Dave S. incorrectly stated mass when he
>should have stated weight.
Dave S. said mass.
Dave S. meant mass.
Dave S. was absolutely correct.
Sure, he could also have said weight. But that wouldn't have been
clear and unambiguous as what he said was ("mass," of course, is also
ambiguous, with several different meanings--but unlike the situation
with "weight," only one of the meanings of "mass" is used with a
number to express its magnitude). Had he said "weight" instead of
"mass," you and many others would likely have misinterpreted it as
having something to do with the strength of the local gravitational
field.
>From my perspective, the respondent about whom Dave S.
>was complaining clearly intended "lbs" as a unit of weight.
So what? Weight is an ambiguous word, one with several different
meanings. Dave S. made clear which one he meant--and he was right.
Yes, those pounds are units of weight. But let's look at the other
pounds still in use today.
First, consider the troy units of weight. That phrase doesn't set off
any alarms with you, I'd bet, nor with anyone else. The troy pounds,
of course, aren't used much any more (and were outlawed in Great
Britain back in the 19th century). But the troy ounces are still in
general use, even enjoying a special exception from the metrication
laws of places such as Australia and the United Kingdom.
But there is one very interesting thing about those troy units of
weight--unlike their avoirdupois cousins, and unlike grams and
kilograms, they have never spawned a unit of force of the same name.
These units of weight remain always units of mass. There is no troy
ounce force and there never has been one.
The other pounds still in use today in various places of Europe and
Latin America are the redefined metric pounds, which replaced many
other old pounds back in the 19th century. They are 500 grams, or
half a kilogram, exactly--units of mass.
I'm sure that you are aware that not everybody uses pounds to measure
this "baggage weight." In fact, most of the people of the world use a
different unit. Don't suppose you could figure out what that might
be, could you? Tell us what those units are. Here's some help:
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=baggage+weight+kg&btnG=Google+Search
Those kilograms are the proper SI units for this baggage weight.
Nobody uses newtons for this weight. Nobody uses poundals for this
weight. Nobody uses kilograms force or pounds force for this weight.
Nor should they.
>The reference to the slug as the English mass unit was only intended as an offhand
>remark. Pounds are units of mass in casual (non-technical) conversations, and
>probably shorthand for "pounds force" in technical conversations.
We don't have separate standards for technical use and for
non-technical use. Either way, a pound is 0.45359237 kg. A pound
force (also, as you point out, often not distinguished from other
pounds) doesn't actually have an official definition, at least in the
United States, but it is 4.448 N and change in any of the definitions
used.
Do I need to go into things like specific impulse, where American
engineers often get this quantity in units of "seconds"? There is, of
course, also an SI unit called a second--but the SI units of specific
impulse are newton seconds per kilogram, or the equivalent meters per
second. Those American engineers only got these pseudo-seconds in the
first place by being sloppy and calling both a unit of force and a
unit of mass by the same name--pound--and then canceling one out with
the other.
Do I need to go into what it means when NASA tells us that the Apollo
11 Lunar Module had a liftoff weight of 10,776.6 lb? Or hundreds of
other similar measurements at various stages of all the Apollo
missions? Selected Mission Weights
http://history.nasa.gov/SP-4029/Apollo_18-37_Selected_Mission_Weights.htm
Do I need to go into things like British thermal units, and specific
heat in Btu/(lb °F)?
Do I need to get into poundals? There's another unit, which like the
slug is only used in a technical context, only to simplify
calculations by making it easier to keep track of the units in the
result of those calculations.
>
>For the record, I don't claim that slugs are the only unit of mass in the English
>system, and I'm sorry to have inadvertantly made that implication.
>
>Russell Kent
Just to make it clear to others who might not pick up on this as
quickly as you did, I'll point out that the most common English units
of mass are pounds, ounces (avoirdupois or troy), and tons (long or
short). Also bushels, as they are used in the commodity markets and
grain elevators today--as a specified amount of mass, different for
various commodities.
Now let's pick up a couple more points from your earlier followup to
your own message as well:
On Mon, 08 Dec 2003 15:19:03 -0600, Russell Kent <r-k...@ti.com>
wrote:
>OK, I know it's bad form to follow-up one's own posting. So sue me. :-)
>
>Gene,
>I see from your signature that this "weight vs. mass" thing is a personal windmill
>for you. Fine. And I see that slug isn't used anymore (pound-force is the term
>now).
Pounds force and slugs are different things. One is a unit of force,
the other a unit of mass. Maybe you are getting mixed up with
poundals, which are units of force in a completely different
different, much older fps system of units. Guess what the units of
mass are in that oldest English system of mechanical units.
> And for non-technical conversations, pound is a unit of mass.
Baggage weight is a measurement of mass, in either a technical or
nontechnical context. Talking about the sale of cheese in a physics
class doesn't change the rules governing its sale. See "Physicist qua
Cheesemonger (U. of Winnipeg)"
http://groups.google.com/groups?safe=images&ie=UTF-8&oe=UTF-8&as_usubject=physicist%20cheesemonger&lr=&hl=en
Pounds are used both as units of mass and as units of force in
technical contexts. Sensible people follow the rules and identify the
recent spinoff as "pounds force": American Society for Testing and
Materials, Standard for Metric Practice, E 380-79, ASTM 1979:
3.4.1.4 The use of the same name for units of force
and mass causes confusion. When the non-SI units
are used, a distinction should be made between
force and mass, for example, lbf to denote force in
gravimetric engineering units and lb for mass.
>Here's a question though: is this forum a technical or non-technical conversation?
That would be one of the least reliable clues to the meaning of any
words used here.
>And look at the sequence of postings: EUTNET wrote that the baggage area dimension
>was 100 lbs, obviously meaning *weight*, and Dave S. complained that EUTNET
>"cannot tell the difference between MASS and VOLUME." [emphasis Dave's] So I
>believe Dave should have instead written "WEIGHT and VOLUME."
You believe wrong.
>Now I suspect that Dave S. was merely careless and really does understand the
>difference between mass and weight, and I was trying to gently pass along the
>advice that newsgroup corrections are invariably inspected for even the slightest
>error (see this thread!). I welcome you (Gene) jumping in at that point to
>correct the whole weight vs. mass, slugs, pound-force hullabalu, but I wish you'd
>do it with a bit less hostility. Someone may well have pissed in your cornflakes,
>but I assure you it wasn't me. :-)
>
>Russell Kent
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
Gene Nygaard
Shirt) wrote:
Well, now, in this fuzzy dreamworld you inhabit, what exactly is the
standard for a pound?
What is the nature of this standard? Something electrical, something
mechanical, or what?
Who made it the standard? When exactly was it made the standard (just
the year will do)?
Where is the standard kept, and who maintains it?
Now for the bonus question:
In addition to the system in which slugs are the units of mass, there
is another, much older English foot-pound-second system in which the
poundal is the derived unit of force. It is the force which will
accelerate the base unit of mass in this oldest English subsystem of
coherent mechanical units at a rate of 1 ft/s². Now, fill in the
blank, please: The base unit of mass in this oldest fps system is the
_____________. (Hint: it is the "p" in this fps system.)
When the poundal system was invented back around 1879, not only did
slugs not exist but also pounds force had never been well-defined
units. This was before anybody ever started picking some "standard
acceleration of gravity" which is an essential ingredient in the
definition of those pounds force. Even today, pounds force don't have
an official definition, at least in the United States. We often
borrow the value for the standard acceleration of gravity which is
official (adopted by the CGPM in 1901, long after the poundal system
was in use and the dyne system in cgs units) for the purpose of
defining kilograms force, i.e. 9.80665 m/s². But other values are
also used for this purpose, such as 32.16 ft/s² (you still commonly
see this used in ballistics with a formula for kinetic energy in a
foot-grain-pound force-second system E = m v²/450240).
Corrie
Channeling a curmudgeon for some reason - must be the fact that I've
been getting skunked by the weather for two weeks.
> Well, now, in this fuzzy dreamworld you inhabit, what exactly is the
> standard for a pound?
Probably the original standard was 1.397 the weekly average of the
King's morning BM.
> What is the nature of this standard? Something electrical, something
> mechanical, or what?
Scatalogical
> Who made it the standard? When exactly was it made the standard (just
> the year will do)?
The King, of course, who else? And of course it changed from
generation to generation, just like the inch.
> Where is the standard kept, and who maintains it?
A silver "repository" in a palace somewhere.
> Now for the bonus question:
>
> In addition to the system in which slugs are the units of mass, there
> is another, much older English foot-pound-second system in which the
> poundal is the derived unit of force. It is the force which will
> accelerate the base unit of mass in this oldest English subsystem of
> coherent mechanical units at a rate of 1 ft/s². Now, fill in the
> blank, please: The base unit of mass in this oldest fps system is the
> _____________. (Hint: it is the "p" in this fps system.)
>
> When the poundal system was invented back around 1879, not only did
> slugs not exist but also pounds force had never been well-defined
> units. This was before anybody ever started picking some "standard
> acceleration of gravity" which is an essential ingredient in the
> definition of those pounds force. Even today, pounds force don't have
> an official definition, at least in the United States. We often
> borrow the value for the standard acceleration of gravity which is
> official (adopted by the CGPM in 1901, long after the poundal system
> was in use and the dyne system in cgs units) for the purpose of
> defining kilograms force, i.e. 9.80665 m/s². But other values are
> also used for this purpose, such as 32.16 ft/s² (you still commonly
> see this used in ballistics with a formula for kinetic energy in a
> foot-grain-pound force-second system E = m v²/450240).
Let's keep it simple and just use kilograms x furlongs /
fortnight^2...
B2431
>
>Let's keep it simple and just use kilograms x furlongs /
>fortnight^2...
>
You were almost right. It's (stones * furlongs)/ (fortnight^2 + f) where f =
fudge factor.
It's all basic math. Example 2 + 2 = 4 unless you uses very large values of 2.
Dan, U. S. Air Force, retired
Rick Poole
I too need the answer to this and was planning on taking detailed pictures
of an RV-7A baggage compartment if I ever get the chance to look closely at
one. My concern was not so much weight capacity but how easy it is to fit
items into the compartment and what size items would fit. I remember
looking at an RV-6 a few years ago at Sun 'n Fun and thought it odd that
there were some straps or cables over the top of the compartment going from
the seat backs to the back of the baggage compartment. The owner was not
there to ask about them and I don't remember if that was common to most of
the RV-6s I looked at or just that one.
Are there any RV-7/7A owners out there who could post some pictures and
dimensions?
Rick Poole
nospamr...@comcast.net
Remove "nospam" to email
"Dave S" <Doggt...@earthlink.net> wrote in message
news:uc1Ab.326$7p2...@newsread2.news.atl.earthlink.net...
rip
32 threads per inch. Go figure.
Gig Giacona
"Rick Poole" <nos...@nospam.com> wrote in message
news:mgxBb.351047$ao4.1176226@attbi_s51...
SNIP
> I remember
> looking at an RV-6 a few years ago at Sun 'n Fun and thought it odd that
> there were some straps or cables over the top of the compartment going
from
> the seat backs to the back of the baggage compartment. The owner was not
> there to ask about them and I don't remember if that was common to most of
> the RV-6s I looked at or just that one.
>
Think about it for a second. You have a 40 or 50 lbs object behind your head
traveling in a vehicle that is going 150 mph. If the vehicle decelerates of
stops suddenly what is going to happen to that object?
Hint: The cables or straps were tie downs.
Fred the Red Shirt
> Shirt) wrote:
>
> >Russell Kent <r-k...@ti.com> wrote in message news:<3FD4F099...@ti.com>...
> >>
> >>
> >> I'm sorry, you're correct. I didn't mean to imply that they are the only unit of
> >> mass. I was taught (perhaps incorrectly) that the unambiguous term for weight
> >> (scientific meaning) in the English system was "slugs". Apparently it's also
> >> "pounds force" now (it may have been them, too, and I've just forgotten it).
> >
> >I think you mistyped. 'Slugs' are unambiguously a unit of mass.
> >
> >Pounds are ambiguously a unit of force. Ambiguity exists because it
> >is popular in some disciplines to use a unit of mass defined (loosely)
> >as that mass which weighs one pound.
> >
> >But you knew that.
>
> Well, now, in this fuzzy dreamworld you inhabit, what exactly is the
> standard for a pound?
>
HFC? In what fuzzy dreamworld that you inhabit is a slug ambiguous
but the pound is not?
If I say that I weigh 165 lbs (I'd be lying but that's not relevent)
it is ambiguous if I mean pounds force or pounds mass. But if I
say that atmospheric pressure at sea level is 14.7 psi then I
unabiguously mean pounds force per square inch because pressure is
force per unit area.
If I say that I dropped a 15 slug rock on my foot that unambiguously
implies mass.
Is that really so hard to understand?
--
FF
Gene Nygaard
Shirt) wrote:
No argument about those points.
I was merely pointing out that you have it ass-backwards. There is
absolutely no looseness in the use of pounds as units of mass. Pounds
have always been units of mass, and they are now, since a 1959
international agreement, defined around the world as 0.45359237 kg
exactly. See the current U.S. law, and a discussion of the prior U.S.
definition as a slightly different exact fraction of a kilogram for 66
years before then, and a discussion of the international agreement at
one of these sites (same document):
http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf
http://gssp.wva.net/html.common/refine.pdf
It is pounds force that are the recent spinoff, not the other way
around. It is pounds mass that are the venerable units, and pounds
force which are the bastardization, not the other way around.
It is pounds force which were never well defined before the 20th
century. It is pounds force which don't even have an official
definition today.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
Russell Kent
> Russell Kent <r-k...@ti.com> wrote in message news:<3FD4F099...@ti.com>...
> >
> >
> > I'm sorry, you're correct. I didn't mean to imply that they are the only unit of
> > mass. I was taught (perhaps incorrectly) that the unambiguous term for weight
> > (scientific meaning) in the English system was "slugs". Apparently it's also
> > "pounds force" now (it may have been them, too, and I've just forgotten it).
>
> I think you mistyped. 'Slugs' are unambiguously a unit of mass.
Oy. You are correct, sir.
> Pounds are ambiguously a unit of force. Ambiguity exists because it
> is popular in some disciplines to use a unit of mass defined (loosely)
> as that mass which weighs one pound.
>
> But you knew that.
Ibid. :-)
Russell Kent
Dave Hyde
> Hint: The cables or straps were tie downs.
Another hint. On RVs, the cables that run from the
seat backs to the upper part of the baggage area
are part of the shoulder harnesses.
Dave 'no-load' Hyde
na...@brick.net
Fred the Red Shirt
>
> I was merely pointing out that you have it ass-backwards. There is
> absolutely no looseness in the use of pounds as units of mass.
Non-sequitor. Loosness was never at issue. At issue was ambiguity.
Pounds can be either a unit of mass or a unit of force and often that
is not even made clear by the context. That pretty well fits the
defintion of ambiguous, does it not?
Slugs, OTOH, are only defined as units of mass. No ambiguity there.
The OP referred to slugs as ambiguous. The OP had it bass akwards.
--
FF
>
> It is pounds force that are the recent spinoff, not the other way
> around. It is pounds mass that are the venerable units, and pounds
> force which are the bastardization, not the other way around.
>
Was not the pound ever defined as a unit of weight? If it was
defined as a unit of weight then it was simultaneously defined as
a unit of force without regard to whether or not the person(s)
defining it UNDERSTOOD that they were doing so.
E.g. in your researches, what is the earliest definion of pound that
you can find?
--
FF
Gene Nygaard
Shirt) wrote:
>Gene Nygaard <gnyg...@nccray.com> wrote in message news:<s5eetvokkvpp7jijg...@4ax.com>...
>> On 10 Dec 2003 06:50:50 -0800, fredf...@spamcop.net (Fred the Red
>> Shirt) wrote:
>>
>
>>
>> I was merely pointing out that you have it ass-backwards. There is
>> absolutely no looseness in the use of pounds as units of mass.
>
>Non-sequitor. Loosness was never at issue.
It was after you brought it up, saying: "Ambiguity exists because it
is popular in some disciplines to use a unit of mass defined (loosely)
as that mass which weighs one pound."
In actual fact, pounds are defined very specifically as 0.45359237 kg
exactly. You don't get there by starting with a pound force. You can
use that definition, in conjunction with some value for a standard
acceleration of gravity (and none has ever been officially adopted for
this purpose, so there are a few different values which are used for
this), to define a pound force.
If your confusion about this were an isolated problem suffered by you
individually, it would hardly be worth comment. But the fact of the
matter is that this confusion is also shared by several authors of
physics textbooks, and many science teachers at various levels. You
could easily find textbooks and web sites making the same claims that
you made, many not merely implying but specifically stating that
pounds mass are a substandard derivative of the pound as a unit of
force--there is in fact widespread, systematic miseducation on this
point.
>At issue was ambiguity.
>Pounds can be either a unit of mass or a unit of force and often that
>is not even made clear by the context. That pretty well fits the
>defintion of ambiguous, does it not?
>
>Slugs, OTOH, are only defined as units of mass. No ambiguity there.
>
>The OP referred to slugs as ambiguous. The OP had it bass akwards.
No. Russell Kent originally claimed that pounds ARE NOT units of
mass. As he did so, he claimed that slugs are the English units of
mass.
Then later, after he learned that pounds are indeed units of mass, as
well as pounds force, he got confused about what slugs are. He then
twice claimed that slugs are units of force.
But he never called slugs ambiguous nor implied that slugs are
ambiguous. He never claimed, in either message, that slugs could be
both units of mass and units of force. He was just confused in the
second message. So it is fine that you called him on that, and
pointed out that he was wrong--but in the process, you introduced a
new issue about the "looseness" of the definition of a pound as a unit
of mass.
Gene Nygaard
Gene Nygaard
Shirt) wrote:
>Gene Nygaard <gnyg...@nccray.com> wrote in message news:<s5eetvokkvpp7jijg...@4ax.com>...
>> On 10 Dec 2003 06:50:50 -0800, fredf...@spamcop.net (Fred the Red
>> Shirt) wrote:
>>
>
>>
>> I was merely pointing out that you have it ass-backwards. There is
>> absolutely no looseness in the use of pounds as units of mass.
>
>Non-sequitor. Loosness was never at issue. At issue was ambiguity.
>Pounds can be either a unit of mass or a unit of force and often that
>is not even made clear by the context. That pretty well fits the
>defintion of ambiguous, does it not?
>
>Slugs, OTOH, are only defined as units of mass. No ambiguity there.
>
>The OP referred to slugs as ambiguous. The OP had it bass akwards.
>
>--
>
>FF
>
>
>>
>> It is pounds force that are the recent spinoff, not the other way
>> around. It is pounds mass that are the venerable units, and pounds
>> force which are the bastardization, not the other way around.
I missed this part last time--I saw your signature above in the bottom
of the window, and assumed that the above was all you had written, and
didn't scroll down to see the rest and didn't see it when I replied
either.
>
>Was not the pound ever defined as a unit of weight?
Certainly. But that doesn't mean "not mass."
Look at the millions of items in the grocery stores and in the
pantries of our homes today that list the "net weight" of our foods
and various other hardware and automotive products. The pounds on
them are every bit as much units of mass as the grams which appear
right alongside them.
Like I pointed out to Russell a long time ago in this thread, the troy
system of weights also includes pounds and ounces. But unlike their
avoirdupois cousins, and unlike grams and kilograms, the troy units of
weight are always units of mass. They have never spawned units of
force of the same name.
What's really strange is that there are always some fools who will
insist that when we buy and sell goods by weight, we'd want to measure
some quantity that varies with location. How stupid can some people
be?
Get it through your thick skull that "weight" is an ambiguous word,
one with several different meanings. Note also that "net weight" is
not a physics term. If you are talking about a "weight" which is the
force due to gravity, then you can't ignore the container, unless
you've invented something that is invisible to gravity. Whenever
anybody talks about "net weight," that weight is the very same thing
as what physicists often call "mass" in their jargon.
>If it was
>defined as a unit of weight then it was simultaneously defined as
>a unit of force without regard to whether or not the person(s)
>defining it UNDERSTOOD that they were doing so.
Bullshit.
The meaning of "weight" which is a synonym for "mass" in physics
jargon is quite proper and legitimate, well justified in history and
in linguistics and in the law.
It is, in fact the original meaning of the word weight, which entered
Old English over 1000 years ago meaning the quantity measured with a
balance. That quantity is, of course, mass--not force due to gravity.
Those balances were, of course, the only weighing devices anybody had
ever used even 200 years ago, and people had been weighing things for
something like 7000 years or more before then.
What you need to do is to take a look at how the standards for a pound
were propogated throughout the world. If someone made a copy of the
standard maintained at London, and took it to South Africa or to
Washington, D.C. or whereever, what exactly is it that is the same
about the pound in the new location? It exerts a different amount of
force in the new location, but it is still the same mass.
Maybe you should take a look at what the experts in the field have to
say about it, people such as the keepers of our standards. For
example, the national standards laboratories of the United Kingdom and
of the United States:
Here's a FAQ by the NPL, the national standards laboratory of the
U.K.:
http://www.npl.co.uk/force/faqs/forcemassdiffs.html
Weight
In the trading of goods, weight is taken to mean the
same as mass, and is measured in kilograms. Scientifically
however, it is normal to state that the weight of a
body is the gravitational force acting on it and hence
it should be measured in newtons, and this force
depends on the local acceleration due to gravity.
To add to the confusion, a weight (or weightpiece)
is a calibrated mass normally made from a dense
metal, and weighing is generally defined as a
process for determining the mass of an object.
So, unfortunately, weight has three meanings
and care should always be taken to appreciate
which one is meant in a particular context.
Note--they clearly refer to different *meanings* of this word.
Here's NIST, the U.S. national standards agency, in their Guide for
the Use of the International System of Units, NIST Special Publication
811,
http://physics.nist.gov/Pubs/SP811/sec08.html
In commercial and everyday use, and especially in common
parlance, weight is usually used as a synonym for mass.
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
the briefcase weighs 6 kg
Net wt. 227 g
Note especially that last one--this is the proper usage for the sale
of chicken.
The National Standard of Canada, CAN/CSA-Z234.1-89 Canadian Metric
Practice Guide, January 1989:
5.7.3 Considerable confusion exists in the use of the
term "weight." In commercial and everyday use, the
term "weight" nearly always means mass. In science
and technology, "weight" has primarily meant a force
due to gravity. In scientific and technical work, the
term "weight" should be replaced by the term "mass"
or "force," depending on the application.
5.7.4 The use of the verb "to weigh" meaning "to
determine the mass of," e.g., "I weighed this object
and determined its mass to be 5 kg," is correct.
The thing to note here is the different treatment of the noun forms
and the verb forms, Contrast the application dependent meanings of
the former with the unqualified "is correct" in the latter.
The other thing to note is that "nearly always" is much stronger than
"primarily"--they even got that part correct.
Like the experts tell you, you are best off avoiding the word "weight"
in a technical context, and if you do use it, you need to make clear
which meaning is intended.
>E.g. in your researches, what is the earliest definion of pound that
>you can find?
Long before there was an England.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
James R. Freeman
example if we look a W. 105 and move to W. 15 we have moved from a gravity
hole to a gravity peak.The core of the Earth is like spinning a egg, in our
case the core has not come up to the speed of the surface and locations of
higher mass move but give us the 2 valley 2 peak problem in mass/gravity. It
is very much to note if You are doing station keeping on a geo-syn sat. .
"Gene Nygaard" <gnyg...@nccray.com> wrote in message
news:8chitvc1tqlpiigqu...@4ax.com...
Fred the Red Shirt
> On 11 Dec 2003 09:52:27 -0800, fredf...@spamcop.net (Fred the Red
> Shirt) wrote:
>
> >Gene Nygaard <gnyg...@nccray.com> wrote in message news:<s5eetvokkvpp7jijg...@4ax.com>...
> >> On 10 Dec 2003 06:50:50 -0800, fredf...@spamcop.net (Fred the Red
> >> Shirt) wrote:
> >>
>
> >>
> >> I was merely pointing out that you have it ass-backwards. There is
> >> absolutely no looseness in the use of pounds as units of mass.
> >
> >Non-sequitor. Loosness was never at issue. At issue was ambiguity.
> >Pounds can be either a unit of mass or a unit of force and often that
> >is not even made clear by the context. That pretty well fits the
> >defintion of ambiguous, does it not?
> >
> >Slugs, OTOH, are only defined as units of mass. No ambiguity there.
> >
> >The OP referred to slugs as ambiguous. The OP had it bass akwards.
> >
> >--
> >
> >FF
> >
> >
> >>
> >> It is pounds force that are the recent spinoff, not the other way
> >> around. It is pounds mass that are the venerable units, and pounds
> >> force which are the bastardization, not the other way around.
>
> I missed this part last time--I saw your signature above in the bottom
> of the window, and assumed that the above was all you had written, and
> didn't scroll down to see the rest and didn't see it when I replied
> either.
>
> >
> >Was not the pound ever defined as a unit of weight?
>
> Certainly. But that doesn't mean "not mass."
See below regaring how weight is defined differently in differnt
theories.
>
> Look at the millions of items in the grocery stores and in the
> pantries of our homes today that list the "net weight" of our foods
> and various other hardware and automotive products. The pounds on
> them are every bit as much units of mass as the grams which appear
> right alongside them.
I certainly hope that when they quantify the good they mean pounds
mass and not pounds force.
>
> Like I pointed out to Russell a long time ago in this thread, the troy
> system of weights also includes pounds and ounces. But unlike their
> avoirdupois cousins, and unlike grams and kilograms, the troy units of
> weight are always units of mass. They have never spawned units of
> force of the same name.
What you address here is an vagueness in human language, not an
ambiguity in natural law.
>
> What's really strange is that there are always some fools who will
> insist that when we buy and sell goods by weight, we'd want to measure
> some quantity that varies with location. How stupid can some people
> be?
I never found any who wanted to do that, nor anyone who does
because on a practical level wherever the measurement is made,
even if it is made by actually measuring force, the variance
is so small that most normal folks consider in negligible, or
rather it IS so negligible that no one has any reason to consider
it at all. I'll be damned if I can understand why you find that
miniscule variance to be so disconcerting.
>
> Get it through your thick skull that "weight" is an ambiguous word,
I understood that already and am quite prepared to explain it.
In Newtonian Physics, 'weight' is a force. Mass OTOH is the factor of
proportionality between force and acceleration.
In General Relativity, 'weight' is a geometrial distortion of
space-time due to the presence of mass.
So weight is either a force or a geometrical effect, depending on
which model you happen to be using at the time.
In common parlance, 'weight' is either or both, or even mass,
or most often, none of the the above because in common parlance,
one generally does not assume any specific physical theory and
it is quite common for people to use words without regard to any
formal definiton at all.
> one with several different meanings. Note also that "net weight" is
> not a physics term. If you are talking about a "weight" which is the
> force due to gravity, then you can't ignore the container, unless
> you've invented something that is invisible to gravity. Whenever
> anybody talks about "net weight," that weight is the very same thing
> as what physicists often call "mass" in their jargon.
Are you unfamiliar with the concept of the superposition of forces?
>
> >If it was
> >defined as a unit of weight then it was simultaneously defined as
> >a unit of force without regard to whether or not the person(s)
> >defining it UNDERSTOOD that they were doing so.
>
> Bullshit.
>
> The meaning of "weight" which is a synonym for "mass" in physics
> jargon
Can you state the formal name any internally consistant physical
theory in which weight and mass are synonyms? As illustrated above,
that is true of neither Newtonian Physics, nor General Relativity.
I know of no physical theory, nor any physicist that uses the words
weight and mass interchangeably within the discipline of physics
itself.
> is quite proper and legitimate, well justified in history and
> in linguistics and in the law.
Have you never heard the adhomition, 'The law cannot change a fact'?
Surely the same is true of language, see below.
>
> It is, in fact the original meaning of the word weight, which entered
> Old English over 1000 years ago meaning the quantity measured with a
> balance. That quantity is, of course, mass--not force due to gravity.
A thousand years ago the contemporary known models for gravity were
too primitive to distinguish between the two. Thus when the pound
was defined as a unit of weight it was simultaneously defined
as a unit of mass and of force, and for that matter, of space-
time distortion. those folks didn't realize that but that's
doens't change the facts.
>
> Those balances were, of course, the only weighing devices anybody had
> ever used even 200 years ago, and people had been weighing things for
> something like 7000 years or more before then.
Balances of course, are mass comparison devices. When one 'weighs'
something with a balance, or for that matter, by any other method,
and announces it weighs x pounds it is ambiguous, and also usually
unimportant whether that person means weight or mass.
Indeed, I used the example of telling you I weigh 165 pounds.
That tells you how much there is of me without regard to whether
I meant pounds force or pounds mass. Were I on the moon, you might
need clarification.
>
> What you need to do is to take a look at how the standards for a pound
> were propogated throughout the world.
I don't see that I need to do that at all.
> If someone made a copy of the
> standard maintained at London, and took it to South Africa or to
> Washington, D.C. or whereever, what exactly is it that is the same
> about the pound in the new location? It exerts a different amount of
> force in the new location, but it is still the same mass.
>
> Maybe you should take a look at what the experts in the field have to
> say about it, people such as the keepers of our standards. For
> example, the national standards laboratories of the United Kingdom and
> of the United States:
>
> Here's a FAQ by the NPL, the national standards laboratory of the
> U.K.:
> http://www.npl.co.uk/force/faqs/forcemassdiffs.html
>
> Weight
> In the trading of goods, weight is taken to mean the
> same as mass, and is measured in kilograms. Scientifically
> however, it is normal to state that the weight of a
> body is the gravitational force acting on it and hence
> it should be measured in newtons, and this force
> depends on the local acceleration due to gravity.
See? I'm right.
> To add to the confusion, a weight (or weightpiece)
> is a calibrated mass normally made from a dense
> metal, and weighing is generally defined as a
> process for determining the mass of an object.
>
> So, unfortunately, weight has three meanings
> and care should always be taken to appreciate
> which one is meant in a particular context.
>
>
> Note--they clearly refer to different *meanings* of this word.
So it makes perfect sense that since 'weight' is ambiguous as to
whether it means force or mass a standard unit of weight, the
pound, is also ambiguous as to whether it means force or mass
That IS just what I wrote befor, pounds are ambiguous, slugs
are not. Can you get that through YOUR thick skull?
Again, you prove that I was correct to say that pounds are ambiguous
and can be either pound force or pound mass. I was already convinced
of that a long time ago. You do not need to keep proving that I
was right.
>
> The thing to note here is the different treatment of the noun forms
> and the verb forms, Contrast the application dependent meanings of
> the former with the unqualified "is correct" in the latter.
Huh?
>
> The other thing to note is that "nearly always" is much stronger than
> "primarily"--they even got that part correct.
>
> Like the experts tell you, you are best off avoiding the word "weight"
> in a technical context, and if you do use it, you need to make clear
> which meaning is intended.
>
In most applications the ambiguity, if present, is unimportant. For
example, if I am to design a bridge to support 200,000 pounds of traffic
it matters not whether the pounds in that specification are pounds
force or pounds mass so long as the bridge is to be built near the
Earth's surface. As to that variation in the acceleration due to
gravity that worries you so, don't sweat it that's why we use
fators of safety.
If I refer to pressure in psi it is understood that I mean pounds force
becuase pressure if force per unit area.
And if I refer to 100 pounds of hydrazine in a fule tank on a
spacecraft it is clear that I mean pounds mass. (Though I'd rather
use slugs, it makes the calculations easier.)
> >E.g. in your researches, what is the earliest definion of pound that
> >you can find?
>
> Long before there was an England.
>
Which was also long before anyone had enunciated theory of gravity
of sufficient complexity to allow one to differentiate, linguistically
between mass and weight.
I will add, at the risk of causing you a stroke, that the distinction
between mass and weight exists regardless of the language being used
or even if language exists at all. Should we all be struck dumb,
we would not simultaneously become weightless.
--
FF
Fred the Red Shirt
> On 11 Dec 2003 09:52:27 -0800, fredf...@spamcop.net (Fred the Red
> Shirt) wrote:
>
> >Gene Nygaard <gnyg...@nccray.com> wrote in message news:<s5eetvokkvpp7jijg...@4ax.com>...
> >> On 10 Dec 2003 06:50:50 -0800, fredf...@spamcop.net (Fred the Red
> >> Shirt) wrote:
> >>
>
> >>
> >> I was merely pointing out that you have it ass-backwards. There is
> >> absolutely no looseness in the use of pounds as units of mass.
> >
> >Non-sequitor. Loosness was never at issue.
>
> It was after you brought it up, saying: "Ambiguity exists because it
> is popular in some disciplines to use a unit of mass defined (loosely)
> as that mass which weighs one pound."
Which is entirely true.
>
> In actual fact, pounds are defined very specifically as 0.45359237 kg
> exactly.
Which I'll also assume is entirely true (Unless we want to
quibble as to the distinction between dfining a unit of measure
and determining the standard value for that unit, which will
turn on how one defines 'definition'.)
But I would hardly call that a loose definition. If you prefer,
I can elaborate on teh meaning of loose defintion by pointing out
that loosely speaking, pounds mass and pounds force may be circularly
defined.
The pound mass is a mass with a weight of one pound and the pound
force is weight of a one pound mass within the context of weight as
force. We could quibble about where you measure the gravitational
acceleration but then we wouldn't be defining things loosely, would
we.
Now, to establish a standard value for either unit one can use,
a more formal version of at most only one of those defintions.
> You don't get there by starting with a pound force. You can
> use that definition, in conjunction with some value for a standard
> acceleration of gravity (and none has ever been officially adopted for
> this purpose, so there are a few different values which are used for
> this), to define a pound force.
I think you are confusing definition with standardization. One
can define one thing in terms of anther and vice-versa without
need to state any way to determine a standard value for either.
>
> If your confusion about this were an isolated problem suffered by you
> individually, it would hardly be worth comment.
There was no confusion on my part.
You, OTOH, are confabulating defintion, standardization, jargon,
ligusitics, law, pedantry and god knows what else for no apparent
purpose.
> But the fact of the
> matter is that this confusion is also shared by several authors of
> physics textbooks, and many science teachers at various levels. You
> could easily find textbooks and web sites making the same claims that
> you made, many not merely implying but specifically stating that
> pounds mass are a substandard derivative of the pound as a unit of
> force--there is in fact widespread, systematic miseducation on this
> point.
I have found pounds mass to be a poor choice of units for purposes
of most calculations. I prefer to use the slug which is unambiguously
a unit of mass.
If one works first with pounds force, later with pounds mass, then one
is introduced to pounds mass as deriviative of pounds force. Again,
it matters not how the MBS determines the standard value for either.
> >
> >Slugs, OTOH, are only defined as units of mass. No ambiguity there.
> >
> >The OP referred to slugs as ambiguous. The OP had it bass akwards.
>
> No. Russell Kent originally claimed that pounds ARE NOT units of
> mass. As he did so, he claimed that slugs are the English units of
> mass.
I'm not going to check to see if he wrote that or not since that is
not what caught my eye. I'll confirm that he wrote this:
In
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3FD4F099.B6B8A7F2%40ti.com&rnum=4
Russel Kent wrote:
I was taught (perhaps incorrectly) that the unambiguous term for
weight
(scientific meaning) in the English system was "slugs".
>...
> But he never called slugs ambiguous nor implied that slugs are
> ambiguous.
Ok, he referred to slugs as the unambiguos term (not unit) for (not
of)
weight. Which not possible given that weight itself is an ambiguous
term, though not in phyusics in which weight it usually defined by
Newtons law of gravitational attraction.
But you seem to think that it is incorrect to loosely define a thing
if that definition does not strictly follow in a linear fashion, from
a published standard.
If one only defines things in a manner that strictly follows in a
linear fashion from a published standard how could one ever define
a thing 'loosely?'
--
FF
Fred the Red Shirt
> He is right. Gravity is not constant from one location to the next. For
> example if we look a W. 105 and move to W. 15 we have moved from a gravity
> hole to a gravity peak.The core of the Earth is like spinning a egg, in our
> case the core has not come up to the speed of the surface and locations of
> higher mass move but give us the 2 valley 2 peak problem in mass/gravity. It
> is very much to note if You are doing station keeping on a geo-syn sat. .
You can also stay at the same location and exoperience varions
in the _apparent acceleration_ do teo gravity. I wouldn't call that
Gravity not being constant. For Gravity to be inconstant would
require that the Gravitational constant vary.
--
FF
Gene Nygaard
Shirt) wrote:
Good grief. What in the world do you think we've been talking about.
Of course, it is linguistics.
>
>>
>> What's really strange is that there are always some fools who will
>> insist that when we buy and sell goods by weight, we'd want to measure
>> some quantity that varies with location. How stupid can some people
>> be?
>
>I never found any who wanted to do that, nor anyone who does
>because on a practical level wherever the measurement is made,
>even if it is made by actually measuring force, the variance
>is so small that most normal folks consider in negligible, or
>rather it IS so negligible that no one has any reason to consider
>it at all. I'll be damned if I can understand why you find that
>miniscule variance to be so disconcerting.
It is a whopping 0.53%, even if you limit yourself to SEA LEVEL.
Throw in Mt. Chimborazo, the highest mountain on Earth, and it gets
close to 3/4 of a percent; more than 1 part in 140.
Now, if you have a standard 400 oz t bar of platinum, do you suppose
it would make a difference if they were units of force rather than
units of mass? Would three ounces at $600/oz matter?
Buyers of gold and other precious metals were more particular than
that even 2000 years ago.
>
>
>>
>> Get it through your thick skull that "weight" is an ambiguous word,
>
>I understood that already and am quite prepared to explain it.
>
>In Newtonian Physics, 'weight' is a force. Mass OTOH is the factor of
>proportionality between force and acceleration.
>
>In General Relativity, 'weight' is a geometrial distortion of
>space-time due to the presence of mass.
>
>So weight is either a force or a geometrical effect, depending on
>which model you happen to be using at the time.
Those models only explain weight AFTER you have chosen to define it as
the effect of gravity.
>In common parlance, 'weight' is either or both, or even mass,
>or most often, none of the the above because in common parlance,
>one generally does not assume any specific physical theory and
>it is quite common for people to use words without regard to any
>formal definiton at all.
>
>> one with several different meanings. Note also that "net weight" is
>> not a physics term. If you are talking about a "weight" which is the
>> force due to gravity, then you can't ignore the container, unless
>> you've invented something that is invisible to gravity. Whenever
>> anybody talks about "net weight," that weight is the very same thing
>> as what physicists often call "mass" in their jargon.
>
>Are you unfamiliar with the concept of the superposition of forces?
>
>>
>> >If it was
>> >defined as a unit of weight then it was simultaneously defined as
>> >a unit of force without regard to whether or not the person(s)
>> >defining it UNDERSTOOD that they were doing so.
>>
>> Bullshit.
>>
>> The meaning of "weight" which is a synonym for "mass" in physics
>> jargon
>
>Can you state the formal name any internally consistant physical
>theory in which weight and mass are synonyms? As illustrated above,
>that is true of neither Newtonian Physics, nor General Relativity.
There are different quantities involved here. But there is no
"natural law" which tells you what word you should be using for any of
them.
You can choose to call a certain quantity "weight." Your doing so,
however, does not magically erase other meanings which the word
already had.
>I know of no physical theory, nor any physicist that uses the words
>weight and mass interchangeably within the discipline of physics
>itself.
In the first place, what in the world gave you the idea that what
physicists do has anything whatsoever to do with "baggage weight"?
In the second place, it isn't true. Ever heard of atomic weight?
Molecular weight? If not, go look at some of the hundreds of
different periodical tables available on the internet, many from
colleges and universities around the world.
Do you remember the days when atomic weight in physics was different
from atomic weight in chemistry? When one of them defined it based on
oxygen-16 being 16.0000, and the other defined it based on the natural
mix of oxygen isotopes being 16.00000?
>> is quite proper and legitimate, well justified in history and
>> in linguistics and in the law.
>
>Have you never heard the adhomition, 'The law cannot change a fact'?
>Surely the same is true of language, see below.
No "facts" are being changed.
What error do you imagine that the ancient tribesmen of the British
Isles made when they added the word "weight" to Old English over 1000
years ago, with the meaning of a quantity measured with a balance? A
word they used for measuring how much stuff they had, for purposes of
commerce? Something which you admitted yourself, up above, SHOULD BE
mass, and that's exactly what they measured with those balances?
Was the error that these heathens were unable to figure out the
God-given word they were supposed to invent for this purpose?
There was no error then. There is no error today when we use the very
same word "weight," with the very same meaning, for the very same
purposes.
>> It is, in fact the original meaning of the word weight, which entered
>> Old English over 1000 years ago meaning the quantity measured with a
>> balance. That quantity is, of course, mass--not force due to gravity.
>
>A thousand years ago the contemporary known models for gravity were
>too primitive to distinguish between the two. Thus when the pound
>was defined as a unit of weight it was simultaneously defined
>as a unit of mass and of force, and for that matter, of space-
>time distortion. those folks didn't realize that but that's
>doens't change the facts.
The pound was never used to measure force before the 17th century, at
least. It was never a well-defined unit of force before the 20th
century. It doesn't have an "official" definition as a unit of force
even today in the 21st century.
>> Those balances were, of course, the only weighing devices anybody had
>> ever used even 200 years ago, and people had been weighing things for
>> something like 7000 years or more before then.
>
>Balances of course, are mass comparison devices. When one 'weighs'
>something with a balance, or for that matter, by any other method,
>and announces it weighs x pounds it is ambiguous, and also usually
>unimportant whether that person means weight or mass.
>
>Indeed, I used the example of telling you I weigh 165 pounds.
>That tells you how much there is of me without regard to whether
>I meant pounds force or pounds mass. Were I on the moon, you might
>need clarification.
>
>>
>> What you need to do is to take a look at how the standards for a pound
>> were propogated throughout the world.
>
>I don't see that I need to do that at all.
Sure, your other option is to remain stupid.
>> If someone made a copy of the
>> standard maintained at London, and took it to South Africa or to
>> Washington, D.C. or whereever, what exactly is it that is the same
>> about the pound in the new location? It exerts a different amount of
>> force in the new location, but it is still the same mass.
>>
>> Maybe you should take a look at what the experts in the field have to
>> say about it, people such as the keepers of our standards. For
>> example, the national standards laboratories of the United Kingdom and
>> of the United States:
>>
>> Here's a FAQ by the NPL, the national standards laboratory of the
>> U.K.:
>> http://www.npl.co.uk/force/faqs/forcemassdiffs.html
>>
>> Weight
>> In the trading of goods, weight is taken to mean the
>> same as mass, and is measured in kilograms. Scientifically
>> however, it is normal to state that the weight of a
>> body is the gravitational force acting on it and hence
>> it should be measured in newtons, and this force
>> depends on the local acceleration due to gravity.
>
>See? I'm right.
About which of those two definitions?
>> To add to the confusion, a weight (or weightpiece)
>> is a calibrated mass normally made from a dense
>> metal, and weighing is generally defined as a
>> process for determining the mass of an object.
>>
>> So, unfortunately, weight has three meanings
>> and care should always be taken to appreciate
>> which one is meant in a particular context.
>>
>>
>> Note--they clearly refer to different *meanings* of this word.
>
>So it makes perfect sense that since 'weight' is ambiguous as to
>whether it means force or mass a standard unit of weight, the
>pound, is also ambiguous as to whether it means force or mass
That is somewhat time-dependent. But no, one doesn't follow from the
other at all. You could easily have an ambiguous word weight,
measured in newtons for some of its meanings, and measured in
kilograms, even in a world where kilograms were never used as units of
force.
Before pounds force were ever well defined, we had a well-defined
English unit of force: the poundal.
>That IS just what I wrote befor, pounds are ambiguous, slugs
>are not. Can you get that through YOUR thick skull?
No, you went beyond that, and claimed that pounds force came first.
Too stupid to even keep straight what we are dealing with. Here we
are dealing with the ambiguities of the word "weight," not ambiguities
in different units being called pounds.
Pounds are also ambiguous even if you limit them to the mass units,
and even if "weight' is never used as a synonym for mass: we have the
avoirdupois pounds, the troy pounds, other old British units such as
the tower pound and the pound trone, the 500 g pounds still used in
various parts of the world, and the hundreds of other pounds that
those 500 g pounds replaced back in the 19th century.
Furthermore, even if "weight" were not ambiguous, and never a synonym
for mass, we still would have the ambiguity in pounds as both units of
mass and units of force.
>> The thing to note here is the different treatment of the noun forms
>> and the verb forms, Contrast the application dependent meanings of
>> the former with the unqualified "is correct" in the latter.
>
>Huh?
Go take remedial English and learn what a noun and a verb are.
>> The other thing to note is that "nearly always" is much stronger than
>> "primarily"--they even got that part correct.
>>
>> Like the experts tell you, you are best off avoiding the word "weight"
>> in a technical context, and if you do use it, you need to make clear
>> which meaning is intended.
>>
>
>In most applications the ambiguity, if present, is unimportant. For
>example, if I am to design a bridge to support 200,000 pounds of traffic
>it matters not whether the pounds in that specification are pounds
>force or pounds mass so long as the bridge is to be built near the
>Earth's surface. As to that variation in the acceleration due to
>gravity that worries you so, don't sweat it that's why we use
>fators of safety.
>
>If I refer to pressure in psi it is understood that I mean pounds force
>becuase pressure if force per unit area.
>
>And if I refer to 100 pounds of hydrazine in a fule tank on a
>spacecraft it is clear that I mean pounds mass. (Though I'd rather
>use slugs, it makes the calculations easier.)
>
>> >E.g. in your researches, what is the earliest definion of pound that
>> >you can find?
>>
>> Long before there was an England.
>>
>
>Which was also long before anyone had enunciated theory of gravity
>of sufficient complexity to allow one to differentiate, linguistically
>between mass and weight.
We can, however, determine today what they measured then.
We do know what they would have wanted to measure, if they had made
these distinctions. After all, we measure the same thing today for
the same purposes.
What they measured and what they wanted to measure are in total
agreement. So there is no room for you to claim this ambiguity in
ancient times--that only shows up after we start getting engineers in
the modern sense.
>I will add, at the risk of causing you a stroke, that the distinction
>between mass and weight exists regardless of the language being used
>or even if language exists at all. Should we all be struck dumb,
>we would not simultaneously become weightless.
Quite the contrary, this problem is very much a language specific
problem, one that English shares with some other languages such as
French. But it doesn't have to be that way.
For example, when physicists using the Norwegian language were
shopping for a word to use in their jargon for the same things for
which those using English use "weight," they did not choose "vekt"
(various spellings such as vikt, wægt, etc. over time), which is the
cognate of "weight" in English. Instead, they choose an entirely
different word, "tyngde." So Norwegian doesn't have the same
ambiguities that English has.
You can't get a much better indication that the only science involved
here is linguistics, can you?
In case any speaker of the Scandinavian languages sees this, see
Aschehougs Konversasjons Leksikon, H. Aschehoug & Co. (W. Nygaard),
Oslo, Norway, femte utgave, 1972. [No, the publisher is not related
to me, and some of the words were cut off on the photocopy I have so
some letters are replaced by ?]
Vekt (mlt.). 1. Instrument til veiing, se Veieredskaper.
2. Dss. tyngde (s.d.) el. gravitasjon, den kraft et lege øver mot
underlaget når det holdes i likevekt. I daglig brukes v. også ofte i
betydningen masse (s.d.) for å a??? mengden av et stoff. For p unngp
denne tvetydighet bru??? man i fysikken helst ikke betegnelsen v., men
masse og tyngde. Spesifikk vekt, dss. spesifikk tyngde, tyngde pr.
volumen??? tidligere som regel brukt i betydningen tetthet (s.d.) el.
??sitet, masse pr. volumenhet.
Tyngde kalles den kraft som er opphav til den lokale
tyngdeakselerasjon, dvs. til den akselerasjon et legeme får i forhold
til jorden når det faller fritt og uten luftmotstand under påverkning
av Jordens gravitasjonsfelt (tyngdefelt). T. skal angis i et
koordinatsystem som følger Jorden i dens rotasjon, og den blir lik
summen av den lokale gravitasjon og den lokale sentrifugalkraft
(s.d.). Den varierer derfor fra sted til sted. Se Gravitasjon. -- T.
virker på hvert enkelt massepunkt i et legeme, men kan tenkes sat
sammen til en resultantkraft, som er lik summen av tyngden til hvert
enkelt punkt, og som angriper legemet i massemiddelpunktet (s.d.) el.
tyngdepunktet. -- T. brukes også synonymt med gravitasjon.
<end quote>
The same is true in some of the Eastern European languages, according
to what someone told me in another newsgroup a long time ago. I don't
remember the specific language involved then, maybe Hungarian or
Bulgarian or something like that.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
Robert Bonomi
ET <Evil...@pig.com> wrote:
>
[[.. munch ..]]
> .... When I took physics, mass was measured in a.u.'s & I have
>no idea what the a stands for, and I think the u just meant "unit"
a.u.'s are "<a>tomic <u>nits" in *that* context -- The nominal mass of one
proton, in isolation.
Can also be "<a>stronomical <u>unit", a measure of _distance_. The mean
orbital radus of the Earth, around the Sun.
Fred the Red Shirt
unclear, just go back to the earlier articles.]
> >
> >What you address here is an vagueness in human language, not an
> >ambiguity in natural law.
>
> Good grief. What in the world do you think we've been talking about.
> Of course, it is linguistics.
Evidently that is what you have been talking about, not I.
I thought this was clear, but let me carify it now. When I refer
to weight, without modifier, I refer to weight as defined by
Newton's Law of Gravitation and that definition can be written
thus:
W = Gp * (m) / (r^2) Where Gp = G * mp.
G is the gravitational constant
mp is the mass of the planet to which the weight is referred
m is the mass of the body whose weight is in question
r is the distance from that body to the center of mass of
the planet in question (assume a spherical cow, er planet)
* is multiplication
/ is division
^ is exponentiation
2 is an integer greater than one but less than 3
W is then the weight of that body.
One could define weight using different symbols and explain those
symbols in a different language and that would be the SAME definition
of weight, not a different one because scientific definitions are
conceptual, not linguistic.
> >
> >>
> >> What's really strange is that there are always some fools who will
> >> insist that when we buy and sell goods by weight, we'd want to measure
> >> some quantity that varies with location. How stupid can some people
> >> be?
> >
> >I never found any who wanted to do that, nor anyone who does
> >because on a practical level wherever the measurement is made,
> >even if it is made by actually measuring force, the variance
> >is so small that most normal folks consider in negligible, or
> >rather it IS so negligible that no one has any reason to consider
> >it at all. I'll be damned if I can understand why you find that
> >miniscule variance to be so disconcerting.
>
> It is a whopping 0.53%, even if you limit yourself to SEA LEVEL.
>
> Throw in Mt. Chimborazo, the highest mountain on Earth, and it gets
> close to 3/4 of a percent; more than 1 part in 140.
>
> Now, if you have a standard 400 oz t bar of platinum, do you suppose
> it would make a difference if they were units of force rather than
> units of mass? Would three ounces at $600/oz matter?
I sincerely doubt that I shall ever be trading in precious metals
let alone doing so at the summit of Mt Chimborazo. I repeat that
for most folks any difference that results from neglecting the
issue is insignificant.
> >
> >>
> >> Get it through your thick skull that "weight" is an ambiguous word,
> >
> >I understood that already and am quite prepared to explain it.
> >
> >In Newtonian Physics, 'weight' is a force. Mass OTOH is the factor of
> >proportionality between force and acceleration.
> >
> >In General Relativity, 'weight' is a geometrial distortion of
> >space-time due to the presence of mass.
> >
> >So weight is either a force or a geometrical effect, depending on
> >which model you happen to be using at the time.
>
> Those models only explain weight AFTER you have chosen to define it as
> the effect of gravity.
They do not 'explain' weight. They define weight.
> >> >If it [the pound] was
> >> >defined as a unit of weight then it was simultaneously defined as
> >> >a unit of force without regard to whether or not the person(s)
> >> >defining it UNDERSTOOD that they were doing so.
> >>
> >> Bullshit.
> >>
> >> The meaning of "weight" which is a synonym for "mass" in physics
> >> jargon
> >
> >Can you state the formal name any internally consistant physical
> >theory in which weight and mass are synonyms? As illustrated above,
> >that is true of neither Newtonian Physics, nor General Relativity.
>
> There are different quantities involved here. But there is no
> "natural law" which tells you what word you should be using for any of
> them.
Agreed.
>
> You can choose to call a certain quantity "weight." Your doing so,
> however, does not magically erase other meanings which the word
> already had.
Nor do those other meaning prevent you from using that same word
to represent a different concept. It is those concepts I discuss
using (or at any rate attempting to use) language to discuss
those, rather than simply dicussing the language with no regard
for concept.
>
> >I know of no physical theory, nor any physicist that uses the words
> >weight and mass interchangeably within the discipline of physics
> >itself.
>
> In the first place, what in the world gave you the idea that what
> physicists do has anything whatsoever to do with "baggage weight"?
Nothing. I was refering back to your statement:
'The meaning of "weight" which is a synonym for "mass" in physics jargon'
>
> In the second place, it isn't true. Ever heard of atomic weight?
> Molecular weight?
Those are not weights. That the word weight appears in those terms
does not make them weights any more than the use of the word force
in the term 'corriolis force' makes it a force.
>
> Do you remember the days when atomic weight in physics was different
> from atomic weight in chemistry? When one of them defined it based on
> oxygen-16 being 16.0000, and the other defined it based on the natural
> mix of oxygen isotopes being 16.00000?
No, I learned the formal defintion of the mole after it had been
restated based on C-12.
>
> >> is quite proper and legitimate, well justified in history and
> >> in linguistics and in the law.
> >
> >Have you never heard the adhomition, 'The law cannot change a fact'?
> >Surely the same is true of language, see below.
>
> No "facts" are being changed.
My point exactly.
Back to your boheaded pedantistic statement that so many authors
have 'got it wrong' (my paraphrase) when they define the pound
mass to be the mass of an object that weighs one pound. Surley
a liguist such as yourself has sufficient cunning to understand
that authors of textbooks often nay, typically employ esotheric
defintions of terms in common usage for the the purposes of the
curriculum. Thus if within that curriculum the pound force is
defined first then the pound mass may be defined as the mass
of an object which weighs one pound.
Now mind you, I never had a course nor saw a text that actually
bothered to formally define either the pound mass or the pound
force. My physics texts only dealt with formal defintions of
SI units and my engineering texts generally assumed a practical
understanding of units of measure.
But in what order an author chooses to introduce units and
therfore which are derivative of the others may be based,
or dare I say SHOULD be based on the approach the author wishes
to take in teaching the material in question. An engineering
text or physics text is not a text in the history of commerce,
in the history of the standardization of units of measure by
government burocracies, nor of lingusitics and the author need
not slavishly adhere to such histories or histrionics so long
as the bridges designed by his students do not collapse.
These texts are not 'wrong'. Your arguemtn would only show
show them to be wrong if they attributed the author's defintion's
to a standards organisation.
> >>
> >> Here's a FAQ by the NPL, the national standards laboratory of the
> >> U.K.:
> >> http://www.npl.co.uk/force/faqs/forcemassdiffs.html
> >>
> >> Weight
> >> In the trading of goods, weight is taken to mean the
> >> same as mass, and is measured in kilograms. Scientifically
> >> however, it is normal to state that the weight of a
> >> body is the gravitational force acting on it and hence
> >> it should be measured in newtons, and this force
> >> depends on the local acceleration due to gravity.
> >
> >See? I'm right.
>
> About which of those two definitions?
About the ambguity. There are TWO defintions.
>
> >That IS just what I wrote befor, pounds are ambiguous, slugs
> >are not. Can you get that through YOUR thick skull?
>
> No, you went beyond that, and claimed that pounds force came first.
No I claimed that the pound mass could be losely defined based on
the pound force. That is true. I can define pound force first and
pound mass second, as perhaps is done is some texts or more importantly,
I can assume that the reader is famliar with the pound force and not
the pound mass and thus inform the reader that the pund mass may be
define loosely, as the mass of an object that weighs one pound.
>
> What they measured and what they wanted to measure are in total
> agreement. So there is no room for you to claim this ambiguity in
> ancient times--that only shows up after we start getting engineers in
> the modern sense.
I agree that in ancient times the issue was one of vagueness, not
ambiguity.
>
> >I will add, at the risk of causing you a stroke, that the distinction
> >between mass and weight exists regardless of the language being used
> >or even if language exists at all. Should we all be struck dumb,
> >we would not simultaneously become weightless.
>
> Quite the contrary, this problem is very much a language specific
> problem, one that English shares with some other languages such as
> French. But it doesn't have to be that way.
I'll stick to my statement that depriving us of language will not
render us weightless.
>
> For example, when physicists using the Norwegian language were
> shopping for a word to use in their jargon for the same things for
> which those using English use "weight," they did not choose "vekt"
> (various spellings such as vikt, wægt, etc. over time), which is the
> cognate of "weight" in English. Instead, they choose an entirely
> different word, "tyngde." So Norwegian doesn't have the same
> ambiguities that English has.
>
> You can't get a much better indication that the only science involved
> here is linguistics, can you?
I suppose linguistics is a 'science' in the same sense as library
science, political science or (shudder) computer science. And,
yes, I agree that your arguments are entirely linguistic.
--
FF