British imperial unit of mass other than pound mass, slug, and slinch?
Neil Fernandez
pound mass (lbm) (= 1 lb/g)
(= 0.4536 kg)
slug (= 1 lb sec^2/ft, = 1 lb * 1 sec^2/ft = 32.17 lbm)
(= 14.59 kg)
slinch (contraction of 'slug inch', = 1 lb sec^2/inch = 12 slugs)
(= 175.1 kg)
Neil
--
Neil Fernandez
咕rad
"Neil Fernandez" <n...@borve.demon.co.uk> wrote in message
news:VQRvihAxh$0+E...@borve.demon.co.uk...
: Are there any British imperial units of mass other than:
No doubt they will be here if there are;
http://www.convertit.com/Go/Bioresearchonline/Measurement/Units.ASP?Letter=A
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Malcolm Stewart
Farmers' units. e.g. stone
Not sure if these are units of mass or weight! It's a long time since I did A
level.
... or were you only looking for units against which others are defined?
--
M Stewart
Milton Keynes, UK
Neil Fernandez <n...@borve.demon.co.uk> wrote in message
news:VQRvihAxh$0+E...@borve.demon.co.uk...
geoff
<n...@borve.demon.co.uk> writes
the BSBG (BS beer gut)
the 11 o'clock show (aka mass)
now define the Rankin (seriously)
--
geoff
Dave Baker
>slinch?
>From: geoff ge...@ntlworld.com
>Date: 28/05/03 01:30 GMT Daylight Time
>Message-id: <VfX77LDx...@81.100.119.82>
>now define the Rankin (seriously)
Someone found in the garden of unearthly delights maybe ?
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
Neil Fernandez
<malcolm...@megalith.freeserve.co.uk> writes
>Jewellers' measures? e.g. grain, carat.
>Farmers' units. e.g. stone
>Not sure if these are units of mass or weight! It's a long time since I did A
>level.
>... or were you only looking for units against which others are defined?
No - I'd be interested in any unit of mass, but it must measure mass and
not weight. Avoirdupois, troy, apothecaries', whatever. Grain, stone,
and carat are all units of weight, carat nowadays being metric (=0.2 g).
The definition question is interesting, since in the imperial system the
three mass units I'm aware of (pound mass, slug, and slinch) are all
defined in terms of weight (and time and length, which follows). I'm not
sure there was ever a 'basic' imperial unit of mass (?)
Neil
--
Neil Fernandez
John Rumm
From my old Science Data Book:
1 ounce = 0.02834952 kg
16 ounce = 1 pound
14 pound = 1 stone
28 pounds = 1 quarter
4 quarters = 1 hundredweight
20 hundredweight = 1 ton
Weight in imperial (i.e. Force) would be the "Poundal" (or 0.138255 N)
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Andy Dingley
>now define the Rankin (seriously)
Rankine isn't it ? It's a temperature scale, using the same degree
calibration as Fahrenheit, but with the origin moved to absolute zero.
Neil Fernandez
<see.my.s...@nowhere.null> writes
>Neil Fernandez wrote:
>> Are there any British imperial units of mass other than:
>>
>> pound mass (lbm) (= 1 lb/g)
>> (= 0.4536 kg)
>>
>> slug (= 1 lb sec^2/ft, = 1 lb * 1 sec^2/ft = 32.17 lbm)
>> (= 14.59 kg)
>>
>> slinch (contraction of 'slug inch', = 1 lb sec^2/inch = 12 slugs)
>> (= 175.1 kg)
>
>From my old Science Data Book:
>
>1 ounce = 0.02834952 kg
>
>16 ounce = 1 pound
>14 pound = 1 stone
>28 pounds = 1 quarter
>4 quarters = 1 hundredweight
>20 hundredweight = 1 ton
>
>Weight in imperial (i.e. Force) would be the "Poundal" (or 0.138255 N)
Thanks for your reply John, but none of the units you mention are units
of mass - they are all units of weight.
Neil
--
Neil Fernandez
Peter Parry
>now define the Rankin (seriously)
If you mean the Rankine, a temperature scale in which absolute
temperatures are expressed in degrees Fahrenheit so 0degK=0degR and
0degC=491.67 deg R.
If you meant Rankin I have no idea :-)
--
Peter Parry.
http://www.wpp.ltd.uk/
gandalf
>
> Thanks for your reply John, but none of the units you mention are units
> of mass - they are all units of weight.
>
There's always the ancient Anglo-Saxon measure for excess - the Firkin. Used
liberally for both weight and mass, as in: 2 Firkin heavy, or 2 Firkin big. ;-)
John Rumm
>>1 ounce = 0.02834952 kg
>>
>>16 ounce = 1 pound
>>14 pound = 1 stone
>>28 pounds = 1 quarter
>>4 quarters = 1 hundredweight
>>20 hundredweight = 1 ton
>>
>>Weight in imperial (i.e. Force) would be the "Poundal" (or 0.138255 N)
>
>
> Thanks for your reply John, but none of the units you mention are units
> of mass - they are all units of weight.
I personally tend to equate weight with force. Hence the comment about
the poundal.
The above imperial units are now officially defined in terms of
fractions of a kg, and hence are masses not weights. However, I have no
idea what the original definition of the imperial units was, although it
is probably a safe bet that gravity was involved someware. I presume
this is why you considder them as weights rather than mases?
RichardS
Question is, I suppose, what units Newton would have used for the
experimental foundations for his theories.
cheers
Richard
--
Richard Sampson
email me at
richard at olifant d-ot co do-t uk
Malcolm Stewart
news:3ed4a5b9$0$13006$afc3...@news.easynet.co.uk...
> Question is, I suppose, what units Newton would have used for the
> experimental foundations for his theories.
Apples, obviously
Tony Williams
John Rumm <see.my.s...@nowhere.null> wrote:
> I personally tend to equate weight with force. Hence the comment about
> the poundal.
> The above imperial units are now officially defined in terms of
> fractions of a kg, and hence are masses not weights. However, I have no
> idea what the original definition of the imperial units was, although it
> is probably a safe bet that gravity was involved someware. I presume
> this is why you considder them as weights rather than mases?
Yes, my old Kempes implies the same original logic.
When they had to face up to the weight/mass problem
the first move was to define the pound as a Mass
and then to define the pound-force as the force
equal to the weight of a pund mass under standard
gravity. It seems to have gone pear-shaped due to
problems with the exact units to use. Solved pro
tem by defining the Slug.
They seem to have initially gone down the same route
in the metric system, calling the kilogramme a Mass
and inventing the kilogramme-force (or kilopond).
When SI units later came in the definition of these
technical units was made consistent, and of course
only based on the kilogram.
--
Tony Williams.
Peter Parry
<n...@borve.demon.co.uk> wrote:
>Thanks for your reply John, but none of the units you mention are units
>of mass - they are all units of weight.
I thought the pound etc were defined as units of mass in the UK
since the Weights and Measures act of 1878, in the US since 1893 and
by the metrology authorities worldwide since 1959?
http://ourworld.compuserve.com/homepages/Gene_Nygaard/weight.htm
http://futureboy.homeip.net/frinkdocs/faq.html#pound
http://www.npl.co.uk/mass/units.html
http://ts.nist.gov/ts/htdocs/230/235/h4402/appenb.pdf.
http://ts.nist.gov/ts/htdocs/230/235/appxc/appxc.htm
http://physics.nist.gov/Pubs/SP811/appenB9.html
http://www.nwml.gov.uk/faq/faq_metric.asp
Neil Fernandez
<to...@ledelec.demon.co.uk> writes
>In article <rb1Ba.24925$9C6.1...@wards.force9.net>,
> John Rumm <see.my.s...@nowhere.null> wrote:
>
>> I personally tend to equate weight with force. Hence the comment about
>> the poundal.
>
>> The above imperial units are now officially defined in terms of
>> fractions of a kg, and hence are masses not weights. However, I have no
>> idea what the original definition of the imperial units was, although it
>> is probably a safe bet that gravity was involved someware. I presume
>> this is why you considder them as weights rather than mases?
>
> Yes, my old Kempes implies the same original logic.
>
> When they had to face up to the weight/mass problem
> the first move was to define the pound as a Mass
> and then to define the pound-force as the force
> equal to the weight of a pund mass under standard
> gravity. It seems to have gone pear-shaped due to
> problems with the exact units to use. Solved pro
> tem by defining the Slug.
The lb sec^2 per inch (slug inch) has been around for ages. Ditto the
pound force (lbf, or lb for short) and the pound mass (lbm).
Not sure how recent the term 'slug' is.
> They seem to have initially gone down the same route
> in the metric system, calling the kilogramme a Mass
> and inventing the kilogramme-force (or kilopond).
>
> When SI units later came in the definition of these
> technical units was made consistent, and of course
> only based on the kilogram.
You can't define a unit of weight based only on the kilogram, any more
than you can specify the speed of light in terms only of distance.
Neil
--
Neil Fernandez
Keith G. Powell
I think you measure time now by doing a calculation, having taken a
spectroscope to some far way planet to measure the frequency of a
particular line in the spectrum of a particular isotope of an atom of an
element? Scientific measurement has gone far beyond the real every day
experience of "ordinary" people?
What's also confusing and complicating is naming units after scientists.
Keith G. Powell
"Neil Fernandez" <n...@borve.demon.co.uk> wrote
Gene Nygaard
On the contrary--they are all units of weight--and they are all units
of mass. Other units of weight are units of force. Weight is an
ambiguous word, one with more than one meaning.
In some cases above (the pounds, ounces, and tons are probably the
only ones), the same word is now used for a unit of force as well, a
spinoff from the original meaning. There is however no slug force, no
slinch force, no stone force, no hundredweight force (not even for you
fools who think hundred is written in digits as "112").
Consider the troy system of weights. Unlike their avoirdupois
cousins, and unlike grams and kilograms, the troy units have never
spawned units of force of the same name. There is no troy ounce
force, and never has been. Those troy ounces are 31.1034768 g,
exactly, by definition.
What's really strange is that although Great Britain outlawed the troy
pound way back in the 19th century, today in the 21st century the U.K.
still has an explicit exception to its metrication laws for continued
use of the troy ounce.
We no longer have independent standards for avoirdupois pounds either.
They are exactly 0.45359237 kg, by definition. Pounds force are a
different animal, a recent spinoff, something that should be (but of
course, is not always) distinguished from the pounds in their original
definition by identifying them as pounds force, and by using the
symbol "lbf" to distinguish them from the "lb" for the normal pounds
as units of mass.
Of course, in many contexts, kilograms are the proper SI units of
weight. Just as for other definitions of the ambiguous word weight,
newtons are the proper SI units.
NIST Special Publication 811 (1995 ed.),_Guide for the Use of the
International System of Units (SI)_, (by the U.S. national standards
laboratory)
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
NPL (the U.K. national standards laboratory)
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.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/weight.htm
Gene Nygaard
> In article <4bf9ae8...@ledelec.demon.co.uk>, Tony Williams
> <to...@ledelec.demon.co.uk> writes
>
> >In article <rb1Ba.24925$9C6.1...@wards.force9.net>,
> > John Rumm <see.my.s...@nowhere.null> wrote:
> >
> >> I personally tend to equate weight with force. Hence the comment about
> >> the poundal.
>
> >> The above imperial units are now officially defined in terms of
> >> fractions of a kg, and hence are masses not weights. However, I have no
> >> idea what the original definition of the imperial units was, although it
> >> is probably a safe bet that gravity was involved someware. I presume
> >> this is why you considder them as weights rather than mases?
> >
> > Yes, my old Kempes implies the same original logic.
> >
> > When they had to face up to the weight/mass problem
> > the first move was to define the pound as a Mass
> > and then to define the pound-force as the force
> > equal to the weight of a pund mass under standard
> > gravity. It seems to have gone pear-shaped due to
> > problems with the exact units to use. Solved pro
> > tem by defining the Slug.
>
> The lb sec^2 per inch (slug inch) has been around for ages.
An lbf s²/in is not a slug inch. It might be a called a slinch--which
indeed derives from the words slug and inch, but a slug inch would be
something entirely different, a slug times an inch. I've never heard
of the name "slinch" ever being used for this unit other than by a few
people at NASA at some time, though others have used it without a
special name or with a different name.
It has not been around for ages.
Slugs are a 20th century invention, something that didn't appear in
engineering textbooks before the 1920s, and not in physics textbooks
before 1940. They never were used to any significant extent anywhere
outside of the United States and Canada, and even their after a brief
heyday for a couple of decades, they have been steadily decliniing in
use since the 1960s and have now disappeared from physics textbooks
again (along with the rest of the English units).
OTOH, the poundals which John Rumm was talking about have been around
much longer. They have been around since about 1879.
Fill in the blank: the base unit of mass in that oldest coherent
system of English mechanical units, in which the poundal is a derived
unit of force, is the _________.
> Ditto the
> pound force (lbf, or lb for short) and the pound mass (lbm).
Pounds have been units of mass since the Roman times. Pounds force
are a recent invention. They are the ones that need to be
distinguished from the normal "lb" for pounds as units of mass.
Pounds force were never well defined units before about the turn of
the 20th century, when people first started defining a "standard
acceleration of gravity" (or more properly, "of free fall"). It was
1901 when the CGPM officially defined grams force by adopting the
value of 980.665 cm/s² for this purpose. Note that this standard
acceleration of gravity is not a physics quantity--it is strictly a
construct of metrology, serving no other purpose than to define units
of force based on units of mass.
Yes, pounds force had been used in an imprecise manner for a couple of
decades before then, going back at least to the time when James Watt
used the miners' measurements of mass as units of force in determining
the work a mine pony could do over some sustained period of time,
before he arbitarily multiplied this ponypower by 1.5 to get
horsepower.
If I have a pressure gauge labeled in pounds per square inch on a
steam boiler (as on a locomotive for example), it doesn't really
matter if the pressure is 610 lbf/in² or 625 lbf/in², so for these
low-precision applications an ill-defined pound force will work well
enough.
> Not sure how recent the term 'slug' is.
Never used before 1902. See the OED entry. Probably never published
anywhere other than the treatise on fluid dynamics by the person who
coined this word before the 1920s, and still a "paper unit" in 1935.
> > They seem to have initially gone down the same route
> > in the metric system, calling the kilogramme a Mass
> > and inventing the kilogramme-force (or kilopond).
> >
> > When SI units later came in the definition of these
> > technical units was made consistent, and of course
> > only based on the kilogram.
>
> You can't define a unit of weight based only on the kilogram, any more
> than you can specify the speed of light in terms only of distance.
The kilogram IS the proper SI unit for weight in many applications.
To define a unit of force, you need something more than a unit of
mass. But almost always when kilograms are used for something that is
called weight, they are not used as units of force.
Go read what the NPL and NIST and other experts in the field of
"weights and measures" have to say about this. Go figure out what the
word weight means in that phrase "weights and measures," which appears
in the English versions of the names of our international keepers of
the standards, the BIPM, CGPM, and CIPM. Like the International
Bureau of Weights and Measures tells us in the introduction to their
SI brochure (available at http://www.bipm.fr in .pdf format), for the
first half-century or so of their existence, their only responsibility
was the keeping of the standards for mass and length. Take a wild
guess which of those two corresponds to the "Weights" in their English
name.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
Tony Williams
Neil Fernandez <n...@borve.demon.co.uk> wrote:
> In article <4bf9ae8...@ledelec.demon.co.uk>, Tony Williams
> <to...@ledelec.demon.co.uk> writes
[snip]
> > They seem to have initially gone down the same route in the metric
> > system, calling the kilogramme a Mass and inventing the
> > kilogramme-force (or kilopond).
> >
> > When SI units later came in the definition of these
> > technical units was made consistent, and of course
> > only based on the kilogram.
> You can't define a unit of weight based only on the kilogram, any more
> than you can specify the speed of light in terms only of distance.
When I typed 'kilogram' in that last paragraph I
had mass in mind, not weight.
There is weight and mass, and a conflict between the
two because of the variations in gravity.
Initial attempts to resolve the conflict were based around definitions
based on trying to use a standard gravity.... where (say) the
pound-force equals the weight of a *mass* of 1lb when it is under
standard gravity. Similarly for the kg-force and a *mass* of 1kg.
Bit of a bugger's muddle though, needing the subsequent introduction
of technical units, such as the slug.
Force = Mass x Acceleration.
Second go at resolving the problem got shot of gravity, using standard
accelerations instead. The basic units of *mass* were still the pound
and kilogram, and the resultant forces were the poundal and the dyne.
Ok, job done, prob solved.
The next step, SI units, was merely to harmonise the two systems. The
lb, lbf, kgf, poundal and dyne got chopped, and the kilogram became the
basic unit of *mass* and the Newton became the basic unit of force.
--
Tony Williams.
Mark Ayliffe
Tony Williams <to...@ledelec.demon.co.uk> illuminated us with:
>
> The next step, SI units, was merely to harmonise the two systems. The
> lb, lbf, kgf, poundal and dyne got chopped, and the kilogram became the
> basic unit of *mass* and the Newton became the basic unit of force.
Isn't the Newton a Standard unit, rather than a basic one? It's defined in
terms of mass, time and length (kgm/s^2). Aren't the basic (MKS) SI units
kilogram, metre, second, Kelvin and Coulomb? (I'm progressively less sure
about the last two).
--
Mark
Please remove nospam |
to reply by email. | .sdrawkcab dootsrednu tub sdrawrof devil si efiL
www.ayliffe.org |
Nick Nelson
Mark Ayliffe wrote:
> Isn't the Newton a Standard unit, rather than a basic one? It's defined in
> terms of mass, time and length (kgm/s^2). Aren't the basic (MKS) SI units
> kilogram, metre, second, Kelvin and Coulomb? (I'm progressively less sure
> about the last two).
Basic units:
metre, kilogram, second, ampere, kelvin, mole, candela.
according to:
http://www.ex.ac.uk/cimt/dictunit/dictunit.htm#standards
where there are the definitions.
Nick
Mark Ayliffe
Nick Nelson <nick....@man.ac.uk> illuminated us with:
Ah, thank you, that'll teach me to look carefully, still I was nearly
correct! I remember now my puzzlement at the use of the ampere rather than
the coulomb as I'd expect the latter is easier to define in terms of the
charge on a number of moles of electrons, though that might be a little hard
to determine experimentally I suppose!
--
Mark
Please remove nospam | The trouble with ignorance is
to reply by email. | that it picks up confidence as it goes along.
www.ayliffe.org |
Tony Williams
<mark.ayl...@pem.nospam.cam.nospam.ac.uk> wrote:
> On or about Thu, 29 May 2003 at 09:35 GMT, Tony Williams
> <to...@ledelec.demon.co.uk> illuminated us with:
> >
> > The next step, SI units, was merely to harmonise the two systems.
> > The lb, lbf, kgf, poundal and dyne got chopped, and the kilogram
> > became the basic unit of *mass* and the Newton became the basic unit
> > of force.
> Isn't the Newton a Standard unit, rather than a basic one? It's defined
> in terms of mass, time and length (kgm/s^2). Aren't the basic (MKS) SI
> units kilogram, metre, second, Kelvin and Coulomb? (I'm progressively
> less sure about the last two).
My less than precise english.... the casual use of
'basic' in one context, without noticing that it
could get confused with the terminology 'Base Unit'.
The Newton has units of kg.m/sec-squared, so it is
a Derived Unit, derived using three Base Units.
Thanks for the correction.
--
Tony Williams.
Andy Farrall
Andy F
"Tony Williams" <to...@ledelec.demon.co.uk> wrote in message
news:4bfa2da...@ledelec.demon.co.uk...
Chris Hodges
Are you sure about that? In SI the kilogram is mass, the Newton is
force, and therefore weight.
From dictionary.com
Mass (6): Abbr. m (Physics). A property of matter equal to the measure
of an object's resistance to changes in either the speed or direction of
its motion. The mass of an object is not dependent on gravity and
therefore is different from but proportional to its weight.
Weight (2): The force with which a body is attracted to Earth or
another celestial body, equal to the product of the object's mass and
the acceleration of gravity.
Weight (3) a. A unit measure of gravitational force: a table of weights
and measures.
b. A system of such measures: avoirdupois weight; troy weight.
http://physics.nist.gov/cuu/Units/units.html
0.454 kg=1lb and this doesn't depend on your local gravitational field,
so lb are mass.
http://www.ex.ac.uk/cimt/dictunit/ccmass.htm
may be of interest, and so might
http://www.megaconverter.com/Mega2/index.html
but this uses the same list of units for mass and weight. It is a
rather long list though.
--
Chris
-----
Spamtrap in force: to email replace 127.0.0.1 with blueyonder.co.uk
Chris Hodges
> Are there any British imperial units of mass other than:
>
> pound mass (lbm) (= 1 lb/g)
> (= 0.4536 kg)
>
> slug (= 1 lb sec^2/ft, = 1 lb * 1 sec^2/ft = 32.17 lbm)
> (= 14.59 kg)
>
> slinch (contraction of 'slug inch', = 1 lb sec^2/inch = 12 slugs)
> (= 175.1 kg)
>
>
Having read the entire thread so far, I'm still not sure what you're after:
Weight can be used to mean
1) mass (in the groceries sense - in my physics background this would be
considered extremely sloppy).
2) force (mass x freefall acceleration due to gravity).
You seem to want (1) more than (2), but to have some other distinction
between the two.
(Confused)
Ian Johnston
wrote:
: Basic units:
:
: metre, kilogram, second, ampere, kelvin, mole, candela.
The radian and steradian are often added to these.
Ian
Gene Nygaard
(Simon Gardner) wrote:
>In article <j6e9dvcv593chm71n...@4ax.com>,
>Peter Parry <pe...@wpp.ltd.uk> wrote:
>
>> I thought the pound etc were defined as units of mass in the UK
>> since the Weights and Measures act of 1878, in the US since 1893 and
>> by the metrology authorities worldwide since 1959?
>
>No. Both the silly units of length and the daft units of mass still used by
>some of the more primitive boneheads in the UK are these defined purely in
>terms of real units - ie metric standards.
So how does the "no" fit in, when you are not disagreeing with
anything Peter Parry said?
Actually, pounds have always been units of mass. Great Britain's
Weights and Measures Act of 1878 didn't change any definitions of
pounds--the only thing that did with pounds was to outlaw the troy
pound (a unit that has largely fallen out of use everywhere, though it
was never outlawed in the United States, for example) and all its
subdivisions other than the ounce. But the strange thing is that
although Great Britain outlawed the troy pound back in the 19th
century (eff. 1 Jan 1879), in the U.K. today in the 21st century there
is still a silly exception to the metrication laws for the continued
use of the troy ounce.
THose avoirdupois pounds didn't have an independent standard from back
in the time of Henry VIII until after 1850 at least. During that
period, as now, they were defined in terms of a different standard of
mass. Now it is the kilogram, then it was the troy pound. And those
troy units of weight, unlike their avoirdupois cousins, have never
spawned a force unit of the same name. They are always units of mass;
there is no troy pound force, and never has been.
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/
The Natural Philosopher
>
> Are you sure about that? In SI the kilogram is mass, the Newton is
> force, and therefore weight.
Huh?
Where did you do physics?
andrewpreece
"The Natural Philosopher" <a@b.c> wrote in message
news:3ED8FF8B.2020604@b.c...
is a unit of mass, not weight. Weight depends on things like how
fast you are accelerating, or what planet you're on! A kilogram "weight"
has a mass of one kilogram on earth or if it were in freefall in orbit, but
it has a weight of 1kilogram on earth, but nothing if in freefall in orbit.
Force = mass x acceleration. A mass of 1 kilo has a weight ( on earth )
of 1kg x 9.82m/s/s, or 9.82 Newtons. Here weight is the same as force.
Apologies if I have not understood the issue under discussion here,
Andy.