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BonezX
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2 edits
reply to 88615298

Re: Weights and measures

said by 88615298:

said by cowboyro:

No they don't. A kilogram is a kilogram, whether on the Earth at the North Pole or on the bright side of the moon. Same for a meter, same for a liter.

Actually the moon's gravity is 1/6 that of Earth so a kilogram on Earth would be 1/6 kilogram on the moon.

i love when people apply Imperial theory to SI units, it just makes my day.

an LB is a force(F=M*A), not a mass, weight is a measurement of force, a slug is a mass not a force
a Newton is a force, not a mass, a kg is a mass not a force.

gravity is calculated at 9.8m/s^2, or 32.15ft/s^2

Imperial units are arbitrary, where SI units are standardized.

good example, a meter is how long it takes for light to travel in 1/299 792 458 of a second.


cowboyro
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said by BonezX:

i love when people apply Imperial theory to SI units, it just makes my day.
an LB is a force

Actually a lb is a unit for MASS not for force.
1lb is defined as 0.45359237 kilograms.
said by BonezX:

Imperial units are arbitrary, where SI units are standardized.

They are not arbitrary at all. Not any more than SI units. There is a strong, well-defined relationship between imperial and SI units.


DataRiker
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join:2002-05-19
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2 edits

The term pound can refer to a mass or a force. The unqualified term "pound" is ambiguous.

If one wishes to be unambiguous you can refer to either a pound-mass or pound-force.

Or just use the SI units since they are designed to be unambiguous.



cowboyro
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said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.


DataRiker
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join:2002-05-19
00000

4 edits

Weight is a force, so if your going to use some subjective context for reference (which is unwise) lb force would be more fitting.

Since neither of you used "pound-force" [lbf] or "pound-mass" [lbm], any argument that one definition is more correct than the other is extremely silly.

The unqualified "pound" should never ever be used in anything but the most informal oral conversations.



BonezX
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reply to cowboyro

said by cowboyro:

said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.

LB is a measurement of force(weight is called the normal force of an object fyi), the imperial measurement of mass is the slug.


cowboyro
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said by BonezX:

said by cowboyro:

said by DataRiker:

Since the term pound is unqualified it can refer to a mass or a force.

The term pound denotes a mass (when we are talking about "weights"). The pound-force term denotes the gravitational force exerted by a 1lb mass on Earth.

LB is a measurement of force(weight is called the normal force of an object fyi), the imperial measurement of mass is the slug.

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.


BonezX
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said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

»en.wikipedia.org/wiki/Slug_%28mass%29
»en.wikipedia.org/wiki/Normal_force

might want to also look outside the united states of stuck in the past, if you did calculations in the scientific community, or about ~90% of the countries in the world in lb you would be laughed at.


OldCableGuy

@planetcr.net
reply to BonezX

>good example, a meter is how long it takes for light to travel in 1/299 792 458 of a second.

Yeah, that doesn't sound arbitrary or anything.



DataRiker
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join:2002-05-19
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3 edits
reply to cowboyro

said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

This is a rather silly point since force is defined using mass.

When you understand your circular reasoning get back to me.


cowboyro
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reply to BonezX

said by BonezX:

said by cowboyro:

According to NIST it's officially defined as a unit of mass. What some people use it as has no bearing over the official definition.

»en.wikipedia.org/wiki/Slug_%28mass%29
»en.wikipedia.org/wiki/Normal_force

might want to also look outside the united states of stuck in the past, if you did calculations in the scientific community, or about ~90% of the countries in the world in lb you would be laughed at.

The pound is the official unit for mass. Not force, mass.
The slug is a derived unit that makes the 1:1 translation between units of time, length and force so that F=m*a


DataRiker
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4 edits

Force is defined using mass.

If you use pound in science, you will be immediately asked to clarify if you mean force or mass.



DataRiker
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reply to OldCableGuy

it is arbitrary until you once again qualify "in a vacuum"

Science is very particular about details