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Author Topic: How fast does a magnet attract ?..and other magnet questions !  (Read 7070 times)

Offline neilep

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Dear Magnet Experts !


I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?

...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?

I am sure you appreciate the eloquence utilized in my  prevailing upon you my respectful request upon thee to demonstrate your generosity of spirit to  furnish me with an understanding of said magnetic joy.

Thank You

Magnet Enquirer


 

Offline lightarrow

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Dear Magnet Experts !
I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?
...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?
Do you mean which is the magnetic force's speed? It's c (light's speed).
« Last Edit: 06/03/2007 19:15:06 by lightarrow »
 

Offline neilep

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Dear Magnet Experts !
I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?
...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?
Do you mean which is the magnetic force's speed? It's c (light's speed).

YES YES YES !!!..THANK YOU THANK YOU !!

I was really upset that this was not answered...is it c ?...wooo..that's fast !!

Thanks again Alberto !
 

Offline lightarrow

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However, magnetic force is a complicated subject. When your magnet approaches a piece of iron, the magnetic field (which propagates at light's speed) begin to act on the iron atoms making them rotate a little, as a compass needle moves with the earth's magnetic field.
This process, called magnetization, is not as fast, you have to wait some more fractions of seconds to have your complete magnetic force.

Anyway, if you (ideally) had an electromagnet able to produce a perfectly collimated magnetic field, you could attract iron pieces on the moon in 1.28 seconds after switching on your device.
« Last Edit: 07/03/2007 19:25:32 by lightarrow »
 

Offline Bored chemist

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That electromagnet would have an inductance so you could only change the current through it at a finite rate; how do you define the time from "switched off" to "switched on"?
 

Offline lightarrow

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That electromagnet would have an inductance so you could only change the current through it at a finite rate; how do you define the time from "switched off" to "switched on"?
The magnetic field starts propagating exactly the instant you switch on the power for the first time. After you have switched off the power, the current keep circulating for some times, as you say. You wait until the current stops completely and then you switch on the device again.
 

Offline science_guy

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I would guess that the magnetic force is independant of the prescence of things to attract.  As shown in some experiments, the field always takes a certian shape of attraction, which would not be the case if it was dependant on anything.

another thing about magnitism that amazes me is that you could have a magnet the size of a quarter, put it an inch above the ground, and you could pick up a paper clip.  compare the sizes of the quarter vs the Earth, and you will see that A magnetic field is exponentially stronger than a gravity field.
 

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