Weight VS. Mass - What's the difference?

A discussion restricted to the topic of hang gliding.
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jnagyvary
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Weight VS. Mass - What's the difference?

Post by jnagyvary »

From the Oz reports source >> "The short answer is that there is often no difference. A common meaning of "weight" is "mass." While many people may commonly use these terms interchangeably, the long answer is there is a difference. An object that has a mass of 10Kg on earth will have the same mass on the moon or anywhere else. An object that weighs 150lbs on earth will not weigh 150lbs on the moon or anywhere that the gravitational constant differs. I don't understand why someone would promote the misconception that this concept is the same when the same effort could be extended to educate the masses (oops) on the realities?
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Davis
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Post by Davis »

Did people actually read the article?

You'll find it here: http://ourworld.compuserve.com/homepage ... weight.htm

I find it quite funny that people have these reactions (you weren't the only one). If you had read the article (again, from your posting here I assume that you haven't) you would see right where your reaction fits.

BTW, trained as a physicist I am quite aware of the physics meaning of the word weight. I am also aware that language is a lot more flexible than F=ma.

I weigh 86 kilos. I weigh 190 pounds. Put me on a balance beam on the moon and put 86 kilos in the other pan and low and behold I will still weigh 86 kilos. (Don't try this with a spring scale. :-))

Again read the article and open your mind.
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Everard
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Post by Everard »

I remember a trick question when I was in the cadets at school (actually at sixth form college, but let's keep it simple...):

Q: What's the weight of a rifle?

A: It is a lump of metal on a string attached to a cloth that you put down the barrel to clean it.

Actually, they were really heavy rifles. Lee Enfields I think, from World War Two.

Another thing they had there (this was Brockenhurst Sixth Form College in the New Forest on the central south coast of England) was a bungee launched glider. I never got to fly it, but I did see it fly. Two teams of cadets, in their brown WW2 army battledress with black berets, walked across the grass playing field hauling the bungees, which were then pegged into the ground, forming a V with the glider at its apex. The glider was then unpinned from its ground anchor and accelerated to fly across the field at maybe ten feet up.

It was a lightweight conventional glider with an open cockpit, a resembling the original Superfloater rigid hang glider of a few years later, painted silver with RAF roundels on the wings.
I love the smell of napalm - in the morning.
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Davis
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Post by Davis »

World Book Encyclopedia

Sirius

If matter from Sirius B were brought to the earth surface, it would weigh
approximately 120,000 tons per cubic foot (4,000,000 metric tons per cubic
meter).

Author: Sumner Starrfield, B.A., M.A., Ph.D. Professor of Physics/Astronomy,
Arizona State University

Why the mind games, mentally transporting this substance to the earth
surface? What this article is talking about is density in its ordinary
meaning. Density is mass divided by volume. This mass is the same in place
on the star, as it is if it were transported to the surface of the earth.

I suppose that it might be in part an idea that pounds, tons, etc. are only
units of force, and not units of mass. That isn't true. And even if it were
true, then the (short) tons should be converted to newtons, not to metric
tons (which are equal to megagrams).
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UnTuckable
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Re: Weight VS. Mass - What's the difference?

Post by UnTuckable »

If you suddenly go 'weight-less',
you might think Zero G.
If you suddenly go mass-less,
you would be alot of Energy, Oh gee (E=mC2)
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Davis
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Post by Davis »

This is a weighty discussion. I wonder if the masses will comprehend it.
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Jaco Herbst
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Post by Jaco Herbst »

Can you eloborate, B1?
I cannot weight :lol:

Just kidding. I like the wordplay though.

Joke:Off topic?
An engineer, a physicist, a mathematician, and a mystic were asked to name the greatest invention of all times.
The engineer chose fire, which gave humanity power over matter.

The physicist chose the wheel, which gave humanity the power over space.

The mathematician chose the alphabet, which gave humanity power over symbols.

The mystic chose the thermos bottle.

" Why a thermos bottle?" the others asked.<> " Because the thermos keeps hot liquids hot in winter and cold liquids cold in summer."

" Yes -- so what?"

" Think about it." said the mystic reverently. That little bottle -- how does it know?"
Jaco
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UnTuckable
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Post by UnTuckable »

How about?:
Your mass on a glider is relatively constant,
but your weight depends on how many G's you pull.
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