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Author Topic: If a magnet opposes a metal object, does it acquire it's weight?  (Read 2861 times)

Offline thedoc

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Don Dillman asked the Naked Scientists:
   
If a magnet opposes a metal object,  does it acquire it's weight?
What do you think?
« Last Edit: 26/01/2015 13:30:02 by _system »


 

Offline yor_on

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You mean levitating one magnet straight up in sky by another? Sure, if it didn't it would be a mystery.
 

Offline PmbPhy

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Don Dillman asked the Naked Scientists:
   
If a magnet opposes a metal object,  does it acquire it's weight?
What do you think?
A magnet can't oppose a metal object so the question is moot.
 

Offline Ethos_

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Don Dillman asked the Naked Scientists:
   
If a magnet opposes a metal object,  does it acquire it's weight?
What do you think?
A magnet can't oppose a metal object so the question is moot.
I think what Pete is saying is; A magnet can't oppose any object, but like magnetic poles can. If the object in question has magnetic poles, such as another magnet, the north pole of one will oppose the north pole of the other. Likewise, the same is true for the south poles of both.

If a magnetic field is structured around a captured and contained metal object such as a copper slug, the magnetic field will induce a magnetic field within the copper slug. Such experiments only show that the original magnetic field is generating an induced field in the copper object and to say that the original magnetic field is opposing the metal object is misleading.
« Last Edit: 29/01/2015 22:38:14 by Ethos_ »
 

Offline evan_au

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Quote
If a magnet opposes a metal object,  does it acquire it's weight?

Perhaps the questioner was imagining a scenario like this? ...
  • A piece of iron sits on a bathroom scale. The weight is shown as 1 kg. [actually, 1kg force, but don't worry about that...]
  • Far away, a magnet hangs from a spring scale. The weight of the magnet is shown as 0.1kg.
  • Now we slide the bathroom scale (with its lump of iron) under the dangling magnet.
  • The spring scale now registers (say) 0.2kg, and the bathroom scale now registers 0.9kg.
  • So the magnet applies an upward force on the iron, which opposes the downward force of gravity, reducing the reading on the bathroom scale.
  • The magnet transfers this same force to the spring scale, so the weight registered on the scale increases by the same amount.
So I guess you could say that "If a magnet opposes the weight of a metal object, the magnet does acquire the "missing" weight."

In the limiting case, where the magnet is strong enough to cause the iron to jump completely off the bathroom scales, then the magnet "acquires" the entire weight of the iron.
 

Offline yor_on

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Yeah, I should have added that my idea was thought to be done inside a gravitational potential (gravity well), as on Earth. But assuming it has been done here, and I'm sure it has, the mass from the 'levitating magnet' should add to a added weight experienced by a scale, whereupon our first magnet rests. It's masses, acting and being acted upon by masses, and they must have a gravitational relation, although a lot trickier to measure in some 'flat space' as far away from any earth or suns.
 

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