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From: n...@puntnl.niks (Nico Coesel)
Newsgroups: sci.electronics.design,sci.physics
Subject: Re: Energy in a permanent magnet question
Date: Fri, 13 Apr 2012 13:44:21 GMT
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HardySpicer <gyansor...@gmail.com> wrote:

>Suppose I have a permanent magnet and attract a nail a height h from
>the ground. If the nail has mass m then I have done mgh of work
>(potential energy)  which must come from the field. If I then attract
>a second nail the magnetic attraction will be less since I have used
>energy when attracting the first one - which is still attached. If I

Magnets don't have anything to do with energy. They exert a force. The
energy comes from whatever is moving/holding the magnet or the object.

-- 
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
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