| Topic: |
Science > Physics |
| User: |
"Don1" |
| Date: |
04 Aug 2005 08:52:05 AM |
| Object: |
Why doesn't SI use newtons? |
Now that they have newtons, why do they persist in using grams and
kilograms when force is meant? Especially when they know that all mass
has volume, and weight?
Could they just be saving face? Afraid of the repercussions if they
admit that they're wrong; that mass is not a fundamental quantity.
Don
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 06:40:54 AM |
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Now that they have newtons, why do they persist in using grams and
kilograms when force is meant? Especially when they know that all mass
has volume, and weight?
Do you see the nonsense that arises from having multiple meanings for
the word "mass?" With regard to units, mass is merely a dimension. To
speak of matter as mass is a type of slang. It is poetic, not
scientific.
If you are talking about grams, kilograms, and force, you don't want to
confuse the situation by calling matter, "mass." Mass is the dimension
of kilograms and grams. Mass is a dimension in the unit of force.
Matter has volume, the dimension of mass does not. Matter has weight
only if the matter is unconnected, but near, another body of matter.
Weight is merely an illusion. The force experienced on the bottom of
the feet is not weight, it is force. "Weight" is a poet's word for
describing force as though it were an attribute of matter.
A body of matter will only have weight if it is near another body of
matter. If the body is freely suspended in space, it still has mass,
but no weight.
Dave
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| User: "PD" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 09:01:37 AM |
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Don1 wrote:
Now that they have newtons, why do they persist
Who is "they"? Most of the "they"s I know do in fact use newtons when
force is meant and they understand the distinction between force and
mass. Wherever I find that kilograms and grams are used, it's in use by
someone who does not understand the distinction between force and mass,
or by someone who is trying to communicate with someone else who
doesn't understand the distinction.
in using grams and
kilograms when force is meant? Especially when they know that all mass
has volume, and weight?
Could they just be saving face? Afraid of the repercussions if they
admit that they're wrong; that mass is not a fundamental quantity.
Don
Could it be that your quixotic quest to return to glory days when the
disinction between mass and force was not understood, and so that
vaguely named units and "a pint's a pound the world 'round" were quite
sufficient, is better aimed at the Amish and other Luddites?
PD
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| User: "Mark Fergerson" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 09:34:31 AM |
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Don1 wrote:
Now that they have newtons, why do they persist in using grams and
kilograms when force is meant?
Who's "they"? I'm familiar with the archaic) terms "gram-force"
and "kilogram-force", but perhaps you don't understand what they mean.
A question for you, Don: what does the term "pound-force" mean,
and why does it exist?
Especially when they know that all mass
has volume, and weight?
Who's "they"? FTM, are you one of "them"?
Could they just be saving face? Afraid of the repercussions if they
admit that they're wrong; that mass is not a fundamental quantity.
Well now; if mass isn't a fundamental quantity (a proposition
with which I agree), how can it occupy volume?
Another question for you Don: my ceiling fan is pushing air with
a measurable, _variable_ force. When it's on "high", does it weigh more?
Mark L. Fergerson
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| User: "Sam Wormley" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 09:12:36 AM |
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Don1 wrote:
Now that they have newtons, why do they persist in using grams and
kilograms when force is meant?
I use newtons...
Ref: http://scienceworld.wolfram.com/physics/Force.html
"The SI unit of force is the newton, equal to 1 kg m s-2. The cgs unit
of force is the dyne, and the British engineering unit of force is the
pound (or, more explicitly, the pound-force). The kilopound is sometimes
also used as a unit of force".
Different units are often used in different disciplines.
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 09:57:05 AM |
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Don1 wrote:
Now that they have newtons, why do they persist in using grams and
kilograms when force is meant? Especially when they know that all mass
has volume, and weight?
Could they just be saving face? Afraid of the repercussions if they
admit that they're wrong; that mass is not a fundamental quantity.
Just what do you mean by a "fundamental quantity"?
AFAIK, in physics we have a myriad of quantities: momentum,
inductance, acceleration, force, voltage, energy, mass, jerk.... to
name a few.
These are all inter-related by various equations, like E=0.5mv^2, V=IR,
and, dare I mention, F=ma.
Nothing in these equations gives any priority to any particular
quantity, except for the presence of one quantity by itself on the
left, which is only a matter of custom.
Now, to devise a set of units for measuring these quantities, one could
define units for each and every quantity; a messy route, since the
equations relating the quantities would need special factors. For
example, if you used furlongs for distance, knots for velocity, and
fortnights for time, d=vt would need a conversion factor to work.
If you pick the right quantities and define units for them, units for
all other quantities can be derived using the equations, removing the
need for any conversion factors (a <<coherent>> system??). In this
sense there are fundamental units amd derived units. In SI, quantities
with defined units are frequency, mass, velocity, and current, so
length, force, and time are derived units.
Now, you <<could>> use force as a fundamental unit, and define mass as
a derived unit, but that leaves you with the problem of finding a good,
fixed, reproducible unit of force.
My two cents worth, anyway...
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| User: "Don1" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 10:34:41 AM |
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wrote:
Don1 wrote:
Now that they have newtons, why do they persist in using grams and
kilograms when force is meant? Especially when they know that all mass
has volume, and weight?
Could they just be saving face? Afraid of the repercussions if they
admit that they're wrong; that mass is not a fundamental quantity.
Just what do you mean by a "fundamental quantity"?
AFAIK, in physics we have a myriad of quantities: momentum,
inductance, acceleration, force, voltage, energy, mass, jerk.... to
name a few.
These are all inter-related by various equations, like E=0.5mv^2, V=IR,
and, dare I mention, F=ma.
Nothing in these equations gives any priority to any particular
quantity, except for the presence of one quantity by itself on the
left, which is only a matter of custom.
Now, to devise a set of units for measuring these quantities, one could
define units for each and every quantity; a messy route, since the
equations relating the quantities would need special factors. For
example, if you used furlongs for distance, knots for velocity, and
fortnights for time, d=vt would need a conversion factor to work.
If you pick the right quantities and define units for them, units for
all other quantities can be derived using the equations, removing the
need for any conversion factors (a <<coherent>> system??). In this
sense there are fundamental units amd derived units. In SI, quantities
with defined units are frequency, mass, velocity, and current, so
length, force, and time are derived units.
Now, you <<could>> use force as a fundamental unit, and define mass as
a derived unit, but that leaves you with the problem of finding a good,
fixed, reproducible unit of force.
My two cents worth, anyway...
That's a good two cents worth; but what I really mean is why isn't SI
called 'A meter-newton-second system? Since 1 kilogram equals 1 newton
second^2per meter = 9.806 65 N second^2per 9.806 65 m . . .
Don
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 07:06:51 AM |
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what I really mean is why isn't SI
called 'A meter-newton-second system? Since 1 kilogram equals 1 newton
second^2per meter = 9.806 65 N second^2per 9.806 65 m
The MKS system is called a meter, kilogram, second system because the
units are built up of these dimensions.
The cgs system is called a centimeter, gram, second system because the
units are built up of these dimensions.
Since meters are simply 100 times larger than centimeters, and
kilograms are 1000 times larger than grams, the real difference between
the MKS and cgs systems is the manner in which the charge dimension is
expressed. In the MKS system of units, charge is expressed as a
dimension of itself (coulomb), while in the cgs system of units charge
is expressed in terms of length, mass, and time.
The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation. Also, the
dimension of charge is awkwardly expressed in terms of the unit of
current. That's like describing bricks in terms of the types of houses
they will build.
Dave
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 02:45:31 PM |
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David Thomson wrote:
what I really mean is why isn't SI
called 'A meter-newton-second system? Since 1 kilogram equals 1 newton
second^2per meter = 9.806 65 N second^2per 9.806 65 m
The MKS system is called a meter, kilogram, second system because the
units are built up of these dimensions.
The cgs system is called a centimeter, gram, second system because the
units are built up of these dimensions.
Since meters are simply 100 times larger than centimeters, and
kilograms are 1000 times larger than grams, the real difference between
the MKS and cgs systems is the manner in which the charge dimension is
expressed. In the MKS system of units, charge is expressed as a
dimension of itself (coulomb), while in the cgs system of units charge
is expressed in terms of length, mass, and time.
The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation.
The major difference is in the base or defined units: in SI they are
frequency, velocity, mass, and current (and something to do with
illumination, and something else to do with angle, maybe). All the
other physical units, like time, distance, momentum, charge, etc, can
be DERIVED from these few DEFINED units. Of course, you can do the
same thing with many different sets of defined units...
dimension of charge is awkwardly expressed in terms of the unit of
current.
....'cause charge is derived, and current is defined.
And the definition is not the least bit awkward if you have to actually
do the calibration.
The best would have been to say that one coulomb was X electrons, and
give the value of X to a whole bunch of sig figs...
And is it any dumber than deriving a unit of energy, dividing by time
to derive a unit of power, then multiplying by a DIFFERENT unit of time
to get a new unit of energy. Joules--> watts--> kilowatt-hours...
It's like using knot-seconds as a unit of distance...
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 08:06:24 AM |
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The major difference is in the base or defined units: in SI they are
frequency, velocity, mass, and current (and something to do with
illumination, and something else to do with angle, maybe). All the
other physical units, like time, distance, momentum, charge, etc, can
be DERIVED from these few DEFINED units. Of course, you can do the
same thing with many different sets of defined units...
Since you are on the topic of definitions, let's clarify a few things.
Time, distance, and charge are not units, they are dimensions.
Dimensions combine with values to produce measurements. Compound
measurements produce units. Units are measurements like seconds,
meters, and coulombs. Units are also combinations of dimensions, such
as momentum being equal to mass times length times frequency. In a
given system of units, the unit of momentum can be defined as one unit
of mass times one unit of length times one unit of frequency. In
modern physics, many units remain undefined, momentum being one of
them.
dimension of charge is awkwardly expressed in terms of the unit of
current.
....'cause charge is derived, and current is defined.
Current is defined by charge. In the MKS and SI systems of units, the
Ampere is equal to one Coulomb times one Hertz. Thus the Coulomb (unit
of charge) must be defined first. What you are probably trying to say
is that current is measured directly, whereas charge is measured
indirectly. But even that would be wrong. An electroscope measures
electrostatic charge directly.
The best would have been to say that one coulomb was X electrons, and
give the value of X to a whole bunch of sig figs...
The reason why charge was not defined as X electrons is because the
measured charge exceeds the predicted number of electrons. This is why
there is a relativistic charge equation, which is pure rubbish. You
would like to think that in a current of 1 amp that there are X number
of electrons passing a certain point. That is the case. But in a
current of 2 amps there are less than 2X electrons passing a certain
point. This is because the charge dimension in the unit of current
does not refer to the electrostatic charge of the electron.
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| User: "Richard Henry" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 12:49:46 PM |
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"David Thomson" <google@volantis.org> wrote in message
news:1123333584.241009.301320@z14g2000cwz.googlegroups.com...
Current is defined by charge. In the MKS and SI systems of units, the
Ampere is equal to one Coulomb times one Hertz.
Ampere = Coulomb * second.
Thus the Coulomb (unit
of charge) must be defined first. What you are probably trying to say
is that current is measured directly, whereas charge is measured
indirectly. But even that would be wrong. An electroscope measures
electrostatic charge directly.
The best would have been to say that one coulomb was X electrons, and
give the value of X to a whole bunch of sig figs...
The reason why charge was not defined as X electrons is because the
measured charge exceeds the predicted number of electrons. This is why
there is a relativistic charge equation, which is pure rubbish. You
would like to think that in a current of 1 amp that there are X number
of electrons passing a certain point. That is the case. But in a
current of 2 amps there are less than 2X electrons passing a certain
point. This is because the charge dimension in the unit of current
does not refer to the electrostatic charge of the electron.
I did not know that.
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 04:56:27 PM |
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Current is defined by charge. In the MKS and SI systems of units, the
Ampere is equal to one Coulomb times one Hertz.
Ampere = Coulomb * second.
The Ampere is equal to potential divided by resistance. Work it out.
It is equal to one Coulomb times one Hertz.
Dave
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 08:06:39 AM |
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The major difference is in the base or defined units: in SI they are
frequency, velocity, mass, and current (and something to do with
illumination, and something else to do with angle, maybe). All the
other physical units, like time, distance, momentum, charge, etc, can
be DERIVED from these few DEFINED units. Of course, you can do the
same thing with many different sets of defined units...
Since you are on the topic of definitions, let's clarify a few things.
Time, distance, and charge are not units, they are dimensions.
Dimensions combine with values to produce measurements. Compound
measurements produce units. Units are measurements like seconds,
meters, and coulombs. Units are also combinations of dimensions, such
as momentum being equal to mass times length times frequency. In a
given system of units, the unit of momentum can be defined as one unit
of mass times one unit of length times one unit of frequency. In
modern physics, many units remain undefined, momentum being one of
them.
dimension of charge is awkwardly expressed in terms of the unit of
current.
....'cause charge is derived, and current is defined.
Current is defined by charge. In the MKS and SI systems of units, the
Ampere is equal to one Coulomb times one Hertz. Thus the Coulomb (unit
of charge) must be defined first. What you are probably trying to say
is that current is measured directly, whereas charge is measured
indirectly. But even that would be wrong. An electroscope measures
electrostatic charge directly.
The best would have been to say that one coulomb was X electrons, and
give the value of X to a whole bunch of sig figs...
The reason why charge was not defined as X electrons is because the
measured charge exceeds the predicted number of electrons. This is why
there is a relativistic charge equation, which is pure rubbish. You
would like to think that in a current of 1 amp that there are X number
of electrons passing a certain point. That is the case. But in a
current of 2 amps there are less than 2X electrons passing a certain
point. This is because the charge dimension in the unit of current
does not refer to the electrostatic charge of the electron.
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 11:50:13 AM |
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David Thomson wrote:
<snip>
Current is defined by charge.
Well, on
http://physics.nist.gov/cuu/Units/ampere.html
the UNIT USED TO MEASURE current is defined in terms of units of force
and distances... No mention of units of charge...
In the MKS and SI systems of units, the
Ampere is equal to one Coulomb times one Hertz.
<<<Note the use of "equal to", rather than "defined as">>>
True of course... And so, to eliminate arbitrary conversion factors in
that formula, units for at most two of these three quantities can be
independently defined. The question is, which two? SI chose the
Ampere and the Hertz; or rather the second, so the Hertz is a derived
unit, contrary to what I belived earlier :(
Thus the Coulomb (unit
of charge) must be defined first.
"Could have been, but wasn't", not "must be"
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 04:49:08 PM |
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Current is defined by charge.
Well, on
http://physics.nist.gov/cuu/Units/ampere.html
the UNIT USED TO MEASURE current is defined in terms of units of force
and distances... No mention of units of charge...
What an excellent example of modern physics befuddling the masses. You
are right, they don't mention charge in their definition of the unit of
current. Yet, what is it that force is acting on between the two
wires?
And still, even though charge was never mentioned as the definition of
the ampere, the ampere is equal to charge times frequency. Just
because you don't see them admitting this in their definition does not
change the fact that it is so.
the Hertz is a derived unit, contrary to what I belived earlier :(
Another excellent example of modern physics and its befuddlement. Time
is derived only in math. The fact is that every clock in the Universe
works by frequency. There is no such thing as a direct measurement of
time.
Dave
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 05:02:44 AM |
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In article <1123243611.775873.167820@o13g2000cwo.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
what I really mean is why isn't SI
called 'A meter-newton-second system? Since 1 kilogram equals 1 newton
second^2per meter = 9.806 65 N second^2per 9.806 65 m
The MKS system is called a meter, kilogram, second system because the
units are built up of these dimensions.
The cgs system is called a centimeter, gram, second system because the
units are built up of these dimensions.
Since meters are simply 100 times larger than centimeters, and
kilograms are 1000 times larger than grams, the real difference between
the MKS and cgs systems is the manner in which the charge dimension is
expressed. In the MKS system of units, charge is expressed as a
dimension of itself (coulomb), while in the cgs system of units charge
is expressed in terms of length, mass, and time.
The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation.
There is a huge difference. It has to do with minimizing
the number of characters a person has to write/read when
doing the math or the paper. The less characters an
expression has, the less the probability that an error
will occur due to misinterpretation.
.. Also, the
dimension of charge is awkwardly expressed in terms of the unit of
current. That's like describing bricks in terms of the types of houses
they will build.
It's easier and more accurate to round the 'number of
bricks used' up to the 'number of houses built'. :-)
Oh, ratzafratz. Or should I have used the word precise
instead of accurate? I always get those two concepts
mixed up.
/BAH
/BAH
Subtract a hundred and four for e-mail.
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 08:01:07 AM |
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The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation.
There is a huge difference. It has to do with minimizing
the number of characters a person has to write/read when
doing the math or the paper. The less characters an
expression has, the less the probability that an error
will occur due to misinterpretation.
In other words, there is little difference between the SI and MKS
systems other than the notation.
.. Also, the
dimension of charge is awkwardly expressed in terms of the unit of
current. That's like describing bricks in terms of the types of houses
they will build.
It's easier and more accurate to round the 'number of
bricks used' up to the 'number of houses built'. :-)
The problem is a little deeper than having convenient quantities. The
same styles of houses can be built from different styles of bricks. As
for the dimension of charge being defined by the unit of current, the
unit of current is supposed to be coulombs per second. But coulombs
are the dimension of charge. So what comes first, the unit or its
dimensions? If current is more fundamental than charge, then charge
must be inseparable from its frequency (current equals charge times
frequency). But static electricity has no frequency.
The SI system is a real mess and only serves to make physics murkier
than it was before.
Dave
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 03:23:37 AM |
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In article <1123246867.703849.297100@g47g2000cwa.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation.
There is a huge difference. It has to do with minimizing
the number of characters a person has to write/read when
doing the math or the paper. The less characters an
expression has, the less the probability that an error
will occur due to misinterpretation.
In other words, there is little difference between the SI and MKS
systems other than the notation.
Just as there is little difference between yards and meters, I
suppose. You aren't really interested in learning which to
use and when, are you?
<snip>
The SI system is a real mess and only serves to make physics murkier
than it was before.
Ah, this is your problem. You find physics to be incomprehensible.
Since this inability cannot possibly be your fault, it must
be the units used.
I suggest that you do 100 dimensional analysis problems using
the long way; IOW, write it all out on paper with a pencil.
/BAH
Subtract a hundred and four for e-mail.
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 07:50:55 AM |
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In other words, there is little difference between the SI and MKS
systems other than the notation.
Just as there is little difference between yards and meters, I
suppose. You aren't really interested in learning which to
use and when, are you?
Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
The problem is a little deeper than having convenient quantities. The
same styles of houses can be built from different styles of bricks. As
for the dimension of charge being defined by the unit of current, the
unit of current is supposed to be coulombs per second. But coulombs
are the dimension of charge. So what comes first, the unit or its
dimensions? If current is more fundamental than charge, then charge
must be inseparable from its frequency (current equals charge times
frequency). But static electricity has no frequency.
The SI system is a real mess and only serves to make physics murkier
than it was before.
Ah, this is your problem. You find physics to be incomprehensible.
Since this inability cannot possibly be your fault, it must
be the units used.
I have spent several years carefully examining the systems of units,
both their weaknesses and their strengths. You would do well to
examine them yourself. I see you are incapable of addressing the
physics with logic, so you resort to pretending I don't understand
physics. That should be a clue for you.
Not only do I understand the concept of dimensions, measurements, and
units better than you, I have also devised a whole new system of units
based upon quantum measurements. You can learn a lot from directly
examining dimensions and units, much more than what the pitiful science
of today teaches.
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
07 Aug 2005 03:38:43 AM |
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In article <1123332655.248441.6360@f14g2000cwb.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
In other words, there is little difference between the SI and MKS
systems other than the notation.
Just as there is little difference between yards and meters, I
suppose. You aren't really interested in learning which to
use and when, are you?
Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
I would use them when the measurements are recorded in
yards, feet or inches or when if I were writing a spec
that needed the conversions.
The problem is a little deeper than having convenient quantities. The
same styles of houses can be built from different styles of bricks. As
for the dimension of charge being defined by the unit of current, the
unit of current is supposed to be coulombs per second. But coulombs
are the dimension of charge. So what comes first, the unit or its
dimensions? If current is more fundamental than charge, then charge
must be inseparable from its frequency (current equals charge times
frequency). But static electricity has no frequency.
The SI system is a real mess and only serves to make physics murkier
than it was before.
Ah, this is your problem. You find physics to be incomprehensible.
Since this inability cannot possibly be your fault, it must
be the units used.
I have spent several years carefully examining the systems of units,
both their weaknesses and their strengths.
You may have examined them for a hundred a years but it would
all be for naught if you've never used them.
.. You would do well to
examine them yourself. I see you are incapable of addressing the
physics with logic, so you resort to pretending I don't understand
physics. That should be a clue for you.
It's clear that you don't since you stated that physics
was incomprehensible. You are the one who stated you didn't
understand.
Not only do I understand the concept of dimensions, measurements, and
units better than you, I have also devised a whole new system of units
based upon quantum measurements.
And do your quantum measurements apply to very large measurements
such as parsecs? How do you calculate these very, very, very
large numbers using a computer?
.. You can learn a lot from directly
examining dimensions and units, much more than what the pitiful science
of today teaches.
Which teaching of science? The PCed, watered down pap that
is presented in kindergarten or the grad level science?
Now, have you done your 100 dimensional analysis problems?
On second thought, do you know what dimensional analysis
is?
/BAH
Subtract a hundred and four for e-mail.
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
09 Aug 2005 10:00:40 AM |
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Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
I would use them when the measurements are recorded in
yards, feet or inches or when if I were writing a spec
that needed the conversions.
Regardless of when you used yards as measurements, that still does not
make them SI or MKS measurements. SI and MKS measurements are always
metric.
Dave
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
10 Aug 2005 03:46:17 AM |
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In article <1123599639.988708.280700@o13g2000cwo.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
I would use them when the measurements are recorded in
yards, feet or inches or when if I were writing a spec
that needed the conversions.
Regardless of when you used yards as measurements, that still does not
make them SI or MKS measurements. SI and MKS measurements are always
metric.
Are you being dense deliberately? You asked about when using
yards was necessary. There is folklore about people who
were unaware that conversions had to be done.
Now, have you done your 100 dimensional analysis problems?
/BAH
Subtract a hundred and four for e-mail.
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| User: "mountain man" |
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| Title: Re: Why doesn't SI use newtons? |
10 Aug 2005 07:18:42 AM |
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<jmfbahciv@aol.com> wrote in message news:b5KdnUfJWI78QmTfRVn-sw@rcn.net...
In article <1123599639.988708.280700@o13g2000cwo.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
I would use them when the measurements are recorded in
yards, feet or inches or when if I were writing a spec
that needed the conversions.
Regardless of when you used yards as measurements, that still does not
make them SI or MKS measurements. SI and MKS measurements are always
metric.
Are you being dense deliberately? You asked about when using
yards was necessary. There is folklore about people who
were unaware that conversions had to be done.
It is not folklore that the western world (western europe
and the british isles) had a standard unit of measurement
as earlier as 4500BC. It was called the megalithic yard.
It was necessary in the placement and construction of
the megalithic structures, and then much later, the pyramids
of Egypt. First proposed in recent times by Thom.
--
Pete Brown
Falls Creek
OZ
www.mountainman.com.au
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
11 Aug 2005 03:30:41 AM |
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In article <CgmKe.78505$oJ.58680@news-server.bigpond.net.au>,
"mountain man" <hobbit@southern_seaweed.com.op> wrote:
<jmfbahciv@aol.com> wrote in message
news:b5KdnUfJWI78QmTfRVn-sw@rcn.net...
In article <1123599639.988708.280700@o13g2000cwo.googlegroups.com>,
"David Thomson" <google@volantis.org> wrote:
Tell us, mighty one, when do you use yards in either the SI or MKS
systems of units?
I would use them when the measurements are recorded in
yards, feet or inches or when if I were writing a spec
that needed the conversions.
Regardless of when you used yards as measurements, that still does not
make them SI or MKS measurements. SI and MKS measurements are always
metric.
Are you being dense deliberately? You asked about when using
yards was necessary. There is folklore about people who
were unaware that conversions had to be done.
It is not folklore that the western world (western europe
and the british isles) had a standard unit of measurement
as earlier as 4500BC. It was called the megalithic yard.
It was necessary in the placement and construction of
the megalithic structures, and then much later, the pyramids
of Egypt. First proposed in recent times by Thom.
I should have qualified my use of the word folklore.
There is computing folklore about one project using
two standards and noone realizing it until the fit
hit the shan.
If you recall a certain crank who posted here, he
would use the yard system no matter what. Now think
about that. Actually, think about that for a very
long time.
/BAH
/BAH
Subtract a hundred and four for e-mail.
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| User: "mountain man" |
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| Title: Re: Why doesn't SI use newtons? |
11 Aug 2005 07:51:39 AM |
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<jmfbahciv@aol.com> wrote:
There is computing folklore about one project using
two standards and noone realizing it until the fit
hit the shan.
There is also the history of the standards in the
width of (interstate) railroad tracks.
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| User: "Richard Henry" |
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| Title: Re: Why doesn't SI use newtons? |
12 Aug 2005 09:34:56 AM |
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"mountain man" <hobbit@southern_seaweed.com.op> wrote in message
news:vRHKe.81157$oJ.3217@news-server.bigpond.net.au...
<jmfbahciv@aol.com> wrote:
There is computing folklore about one project using
two standards and noone realizing it until the fit
hit the shan.
There is also the history of the standards in the
width of (interstate) railroad tracks.
There is a place in California's Owens Valley called Owenyo where the
narrow-gauge Carson & Colorado road coming south from Nevada (eventually
only from Laws to the north and the desert mines to the south) met the
standard-gauge Southern Pacific coming north from LA. There was a
freight-transfer facility built there: a hand-carry freight transfer
platform, a gantry crane, and a dumping trestle to allow narrow-gauge loads
from the mines to be dumped into standard-gauge hoppers headed to
civilization.
Some pictures:
http://www.owensvalleyhistory.com/carson_n_colorado/standard_narrow1.jpg
http://www.owensvalleyhistory.com/carson_n_colorado/owenyo_transfer2.jpg
A map:
http://www.owensvalleyhistory.com/carson_n_colorado/c_c_route_map.jpg
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
12 Aug 2005 02:48:23 AM |
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In article <vRHKe.81157$oJ.3217@news-server.bigpond.net.au>,
"mountain man" <hobbit@southern_seaweed.com.op> wrote:
<jmfbahciv@aol.com> wrote:
There is computing folklore about one project using
two standards and noone realizing it until the fit
hit the shan.
There is also the history of the standards in the
width of (interstate) railroad tracks.
You didn't think long enough. Railroad tracks are
consistent from one end to the other. If they aren't
the first test would result in a train wreck.
Executing computing code once never guarantees consistency.
/BAH
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| User: "mountain man" |
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| Title: Re: Why doesn't SI use newtons? |
12 Aug 2005 09:53:25 AM |
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<jmfbahciv@aol.com> wrote in message news:FrGdnQ6rw4N-6WHfRVn-rQ@rcn.net...
In article <vRHKe.81157$oJ.3217@news-server.bigpond.net.au>,
"mountain man" <hobbit@southern_seaweed.com.op> wrote:
<jmfbahciv@aol.com> wrote:
There is computing folklore about one project using
two standards and noone realizing it until the fit
hit the shan.
There is also the history of the standards in the
width of (interstate) railroad tracks.
You didn't think long enough. Railroad tracks are
consistent from one end to the other. If they aren't
the first test would result in a train wreck.
In Oz in the early days there were three separate rail gauges
scattered between its 7 states, 6 excluding Tazzie. The
early construction was entirely regional, from remotely
disparate geographical (capital city) locations. The
journey itself involved changing trains twice.
Sometimes standards are not perceived
until the picture gets bigger, and the world
smaller. (or vice verse)
Executing computing code once never guarantees consistency.
By definition it is being executed on a physical machine, the operation
of which is more appropriately described by theories of physics
rather than theories of mathematics. Physics never guarantees
consistency.
General Relativity might be refuted by an experiment tomorrow
afternoon, just after lunch.
--
Pete Brown
Falls Creek
OZ
www.mountainman.com.au
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| User: "" |
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| Title: Re: Why doesn't SI use newtons? |
05 Aug 2005 08:18:37 AM |
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In article <1123246867.703849.297100@g47g2000cwa.googlegroups.com>, "David Thomson" <google@volantis.org> writes:
The SI system of units is based upon the MKS system of units. There
really isn't much difference other than in the notation.
There is a huge difference. It has to do with minimizing
the number of characters a person has to write/read when
doing the math or the paper. The less characters an
expression has, the less the probability that an error
will occur due to misinterpretation.
In other words, there is little difference between the SI and MKS
systems other than the notation.
.. Also, the
dimension of charge is awkwardly expressed in terms of the unit of
current. That's like describing bricks in terms of the types of houses
they will build.
It's easier and more accurate to round the 'number of
bricks used' up to the 'number of houses built'. :-)
The problem is a little deeper than having convenient quantities. The
same styles of houses can be built from different styles of bricks. As
for the dimension of charge being defined by the unit of current, the
unit of current is supposed to be coulombs per second. But coulombs
are the dimension of charge. So what comes first, the unit or its
dimensions? If current is more fundamental than charge, then charge
must be inseparable from its frequency (current equals charge times
frequency). But static electricity has no frequency.
Spare us your fatuous *****.
Worrying about what dimensions a unit posseses doesn't change the physics.
What matters is whether the system of units provides a usable,
accurate and reproducible standard for the coulomb, the amp, the
meter, the second and whatever other units that it defines.
Whether this means that the coulomb is defined in terms of the amp
or vice versa and whether this makes the unit dimensions confusing
to you is a personal problem.
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| User: "David Thomson" |
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| Title: Re: Why doesn't SI use newtons? |
06 Aug 2005 07:41:45 AM |
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Worrying about what dimensions a unit posseses doesn't change the physics.
On the contrary, understanding how units construct from dimensions is
the foundation of physics. You are probably one of those arrogant
science snobs who thinks that humans invented dimensions just to make
physics easy to understand. This is why you can't tell the difference
between mass and matter when you do your Relativistic physics. When it
finally dawns on you that dimensions are an actual physical property of
the Universe, you'll finally begin to see the errors of your ways.
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| User: "Clemens W" |
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| Title: Re: Why doesn't SI use newtons? |
04 Aug 2005 11:17:10 AM |
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As always, confusing cart with horse, Don wrote:
jmorriss@idirect.com wrote:
Now, you <<could>> use force as a fundamental unit, and define mass as
a derived unit, but that leaves you with the problem of finding a good,
fixed, reproducible unit of force.
My two cents worth, anyway...
That's a good two cents worth; but what I really mean is why isn't SI
called 'A meter-newton-second system? Since 1 kilogram equals 1 newton
second^2per meter = 9.806 65 N second^2per 9.806 65 m . . .
Don
Fine, Don, now please *define* Newton. As a good, fixed, reproducible
unit of force. Without using the kilogram, of course.
Your turn,
A. Friend
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