Gene Nygaard wrote:
My 'weight' is 230 pounds on earth. That's a fact.

My 'weight' would be 230 pounds on the earth's moon. That's also a
fact.

Your weight is defined as what you weigh on Earth, assuming a
gravitational acceleration of g. Obviously it's not true that your
weight would be measured as 230 pounds on the moon. The CRC Handbook of
Chemistry and Physics states that the weight of a body varies with
location, and defines weight as W = mg, where g is the local
acceleration due to gravity.

Reflecting the apparent dichotomy, the CRC defines the pound both ways:
"1. A unit of mass equal in the U.S. to 0.45359237 kg. exactly.
2. Specifically, a unit of measurement of the thrust or force of a
reaction engine representing the weight the engine can move, as an
engine with 100,000 pounds of thrust. 3. The force exerted on a one
pound mass by the standard acceleration of gravity."

Interestingly, they also define poundal, pound mass and pound weight.
No mention of pound force. Evidently, that would be redundant. ;-)

As an aside, what do you think: Will NASA ever learn the lesson of
the Mars Climate Orbiter, and quite using pounds?

Actually the contractor had specified the thrust of its rocket motor in
pounds. NASA failed to properly convert to the CGS system that it (and
most other scientific organizations) normally use.

73, Jim AC6XG

On Mon, 29 Sep 2003 10:12:33 -0700, Jim Kelley
wrote:



Gene Nygaard wrote:
My 'weight' is 230 pounds on earth. That's a fact.

My 'weight' would be 230 pounds on the earth's moon. That's also a
fact.

Your weight is defined as what you weigh on Earth, assuming a
gravitational acceleration of g. Obviously it's not true that your
weight would be measured as 230 pounds on the moon. The CRC Handbook of
Chemistry and Physics states that the weight of a body varies with
location, and defines weight as W = mg, where g is the local
acceleration due to gravity.

It doesn't cost you any more to pay attention.

Repeat to yourself until you understand it: Weight is an AMBIGUOUS
word. IT HAS SEVERAL DIFFERENT MEANINGS.

The one you cite from the Chemical Rubber Company is, of course, one
of those several definitions. If it always meant the same as mass in
physics jargon, I wouldn't have to point out to you that this is an
ambiguous word, would I?

Didn't you read the message you responded to, especially what
immediately followed the sentence you quoted? Didn't you see what
NIST and ASTM have to say about this? Look at it again, and read it
slowly this time

Let's review what I've already posted in other messages in this
thread, from ASTM

. . . thus, when one speaks of a person's weight,
the quantity referred to is mass. . .

and from NIST

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

Learn to evaluate your sources, also. Those sources are more credible
than any CRC Handbook on this subject.

Your definition of weight is not the proper one to use for your body
weight in the doctor's office or the gym. It is not the one used in
our hospitals. It is not the one used in weighing an NFL lineman at
380 lb, which is equal to 0.98 slinches in one system or 11.8 slugs in
another system of those strange units only used in calculations, only
in the sciences, and only in North America to any significant extent
(people in other English-units countries continued to use the absolute
fps system with force in poundals until they converted to the metric
system in their engineering).

You can, of course, choose not to call this quantity "weight." You
can call it mass instead, if you want to.

But keep in mind that if you do make that voluntary decision, that
fact doesn't prove that anyone else is making an error if they call it
"weight."

Furthermore, it is not an acceptable option to misinterpret what they
are saying, and to misapply an inappropriate definition of weight.

You could, of course, argue that we should all change to your usage.
But you certainly aren't going to exert the effort that would be
necessary get us to give up a word to which we have a prior claim, if
you aren't smart enough to figure out that it would be a change.

Furthermore, to have any hope of success, you'd have to offer us a
verb as well as a noun.

Reflecting the apparent dichotomy, the CRC defines the pound both ways:
"1. A unit of mass equal in the U.S. to 0.45359237 kg. exactly.
2. Specifically, a unit of measurement of the thrust or force of a
reaction engine representing the weight the engine can move, as an
engine with 100,000 pounds of thrust. 3. The force exerted on a one
pound mass by the standard acceleration of gravity."

That really shouldn't come as any surprise to you, does it, at this
stage of the game?

Interestingly, they also define poundal, pound mass and pound weight.
No mention of pound force. Evidently, that would be redundant. ;-)

Have you figured out yet what those poundals are, and how they are
used? What is the base unit of mass in the system in which these
force units are used?

One thing about the CRC Handbook (which edition?) is that they include
stuff put in there over a period of many years, most of it undated.
Those "pounds weight" are an obsolete term for what are now called
pounds force.

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

Gene Nygaard wrote:
You can, of course, choose not to call this quantity "weight." You
can call it mass instead, if you want to.

Here's an interesting quote from _University_Physics_ by Young and
Freedman: "On the moon, a stone would be just as hard to throw
horizontally, but it would be easier to lift." It also says weight
is a vector and mass is a scalar.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil wrote,

Gene Nygaard wrote:
You can, of course, choose not to call this quantity "weight." You
can call it mass instead, if you want to.

Here's an interesting quote from _University_Physics_ by Young and
Freedman: "On the moon, a stone would be just as hard to throw
horizontally, but it would be easier to lift." It also says weight
is a vector and mass is a scalar.
--
73, Cecil http://www.qsl.net/w5dxp


You better watch out, Cecil, Gene is liable to write a scathing indictment
of your intelligence, integrity, and job fitness, for quoting that. By the way,

what ever happened to the old idea that the attraction between two masses
was directly proportional to the size of the two masses multiplied together,
and inversely
proportional to the square of the distance between them - sort of like positive
and
negative charge (Coulomb's Law and all that).
73,
Tom Donaly, KA6RUH

On 30 Sep 2003 18:36:50 GMT, (Tdonaly) wrote:

Cecil wrote,

Gene Nygaard wrote:
You can, of course, choose not to call this quantity "weight." You
can call it mass instead, if you want to.

Here's an interesting quote from _University_Physics_ by Young and
Freedman: "On the moon, a stone would be just as hard to throw
horizontally, but it would be easier to lift." It also says weight
is a vector and mass is a scalar.
--
73, Cecil http://www.qsl.net/w5dxp


You better watch out, Cecil, Gene is liable to write a scathing indictment
of your intelligence, integrity, and job fitness, for quoting that. By the way,

I don't know why I would. I agree with the quoted part. Of course,
though the stone is just as hard to throw, it will likely go farther
before it falls to the ground.

Would you say that a boat is heavy because it is hard to push away
from the dock? What is the relevant factor here--that it is pressing
down with a force due to gravity of 9000 pounds force? Or that it has
a mass of 9000 pounds?

What is the metric equivalent of a ton used for the weight of a U.S.
Navy ship? For example, the tanker USNS Henry J. Kaiser is 27,561
tons deadweight. How much is that is SI units?
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/

Gene Nygaard wrote:
"What is the relevant factor here -- that it is pressing down with a
force due to gravity of 9000 pounds due to gravity of 9000 pounds force?
Or that it has a mass of 9000 pounds?

The tonnage of a ship is the weight of the water it displaces.

The force pressing down (normal force) in mechanical problems is
significant when friction is involved.

Force equals mass time acceleration. So, the mass opposes and increases
the force required to get an object moving, or slowed, for that matter.
That includes a ship. It has inertia and requires force to change its
velocity. Drag is imposed on the submerged portion of the hull,
especially when coated with barnacles.

I shipped out of Long Beach in WW-2 on the LSM 472. I returned to San
Francisco on the LSM 94. I was transferred to the LST 604 to take it up
river to Stockton to be decomissioned and scrapped. While at the ship
yard there I witnessed a curious sight. A large merchant vessel was
moved from one berth to another using a small boat with an outboard
motor as the tow boat. River current in the basin was almost nil, yet it
took several hours to move that large ship with the power of only an
outboard motor. It worked! There must have been nothing more powerful
available and there must have been no rush to get the berth swap made.

Point is that it is likely that neither mass nor weight is as important
as current in many situations. How soon you can get up to speed depends
a lot on mass as Newton predicts. That motorboat would have done its
thing much more quickly with a waterskier in tow than it did with a big
merchant ship in tow.

Best regards, Richard Harrison, KB5WZI

On Wed, 1 Oct 2003 00:36:15 -0500 (CDT),
(Richard Harrison) wrote:

Gene Nygaard wrote:
"What is the relevant factor here -- that it is pressing down with a
force due to gravity of 9000 pounds due to gravity of 9000 pounds force?
Or that it has a mass of 9000 pounds?

The tonnage of a ship is the weight of the water it displaces.

The force pressing down (normal force) in mechanical problems is
significant when friction is involved.

Force equals mass time acceleration. So, the mass opposes and increases
the force required to get an object moving, or slowed, for that matter.
That includes a ship. It has inertia and requires force to change its
velocity. Drag is imposed on the submerged portion of the hull,
especially when coated with barnacles.

I shipped out of Long Beach in WW-2 on the LSM 472. I returned to San
Francisco on the LSM 94. I was transferred to the LST 604 to take it up
river to Stockton to be decomissioned and scrapped. While at the ship
yard there I witnessed a curious sight. A large merchant vessel was
moved from one berth to another using a small boat with an outboard
motor as the tow boat. River current in the basin was almost nil, yet it
took several hours to move that large ship with the power of only an
outboard motor. It worked! There must have been nothing more powerful
available and there must have been no rush to get the berth swap made.

Point is that it is likely that neither mass nor weight is as important
as current in many situations. How soon you can get up to speed depends
a lot on mass as Newton predicts. That motorboat would have done its
thing much more quickly with a waterskier in tow than it did with a big
merchant ship in tow.

So what is the SI equivalent of those 27,561 tons deadweight for that
U.S. Navy ship?

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

Gene wrote,

On 30 Sep 2003 18:36:50 GMT, (Tdonaly) wrote:

Cecil wrote,

Gene Nygaard wrote:
You can, of course, choose not to call this quantity "weight." You
can call it mass instead, if you want to.

Here's an interesting quote from _University_Physics_ by Young and
Freedman: "On the moon, a stone would be just as hard to throw
horizontally, but it would be easier to lift." It also says weight
is a vector and mass is a scalar.
--
73, Cecil http://www.qsl.net/w5dxp


You better watch out, Cecil, Gene is liable to write a scathing indictment
of your intelligence, integrity, and job fitness, for quoting that. By the
way,

I don't know why I would. I agree with the quoted part. Of course,
though the stone is just as hard to throw, it will likely go farther
before it falls to the ground.

Would you say that a boat is heavy because it is hard to push away
from the dock? What is the relevant factor here--that it is pressing
down with a force due to gravity of 9000 pounds force? Or that it has
a mass of 9000 pounds?

What is the metric equivalent of a ton used for the weight of a U.S.
Navy ship? For example, the tanker USNS Henry J. Kaiser is 27,561
tons deadweight. How much is that is SI units?
Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/



Still playing the old one-note samba are we Gene? You must hold the
record for being the most boring guy at the cocktail party. You still
haven't answered my question about why you keep harping on a
question of elementary physics on a newsgroup devoted to
amateur radio antennas. Is this a new species of troll? Is that
all you know how to talk about? When did you first realize you
had this obsession with mass? Are you over-mass?
With the never ending thread about transmission lines, EH antennas,
mass, and the rest, it's pretty obvious what has happened. There's been
an earthquake; all the pots are cracked. Next, someone from the British
Isles will be writing to say gram scales don't MEASURE mass, they only
INDICATE mass.
Brother.
73,
Tom Donaly, KA6RUH

Cecil, W5DXP wrote:
"On the moon, a stone would be just as hard to throw horizontally, but
it would be easier to lift."

The normal forces are different on the earth and moon. But, the physics
book statement follows from Newton: F= MA, and M is the same on earth or
moon.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Cecil, W5DXP wrote:
"On the moon, a stone would be just as hard to throw horizontally, but
it would be easier to lift."

The normal forces are different on the earth and moon. But, the physics
book statement follows from Newton: F= MA, and M is the same on earth or
moon.

I think the point is that the inertia is the same, independent of what
the gravity might happen to be, thus demonstrating the most fundamental
property and defining feature of mass.

73, Jim AC6XG