Re: My dumb experiment with magnets

"Bob" <bobwhite@xxxxxxxxxxxxxx> wrote in message
news:h2Jrh.42642$oA1.21034@xxxxxxxxxxxxxxx
First off, my apologies for asking a dumb question. Obviously I am not a
physics major, but I was wondering about the following experiment.

A supermagnet, as seen advertised on the net, is clamped or glued to a
nonmagnetic surface, perhaps a board.

A cube of iron / steel is placed on the board surface away from the magnet.
As the cube is pushed toward the magnet by a person, at some point the cube
will be rapidly pulled to the magnet, sliding the cube along the board
surface, propelled by the magnetic force, not by any outside force.

Since there was movement of the iron cube by the magnetic force, then by
definition, work was preformed. There was also some, although be it ever so
small, friction of the cube sliding across the surface. Hence there was
some heat, a very small amount, generated by the friction.

Thus, work and heat were generated which requires energy.

If this experiment was conducted a thousand, a million, or an infinite
number of times, then the total distance the iron cube was moved by the
magnetic force would be significant, as would the total heat generated by
friction. This required some amount of energy.

After conducting the experiment a million or so times, is the force of the
supermagnet less than it was at the start of the first experiment?

My guess is that it would be the same. Then, where did the energy required
to move the iron cube and generate heat come from?

Again, sorry if this is a stupid question, but I am curious and appreciate
you putting up with my ramblings.

If you toboggan down a snow-covered hill and then walk
back up and do it again, and again, and again, the total
distance the toboggan has traveled is significant, as
would be the total heat produced by friction.

After conducting this experiment a million or so times,
is the Earth's force of gravity less than it was at the
start of the first toboggan run? Why or why not? Where
did the energy come from to move the toboggan and create
the heat?

If you say "From me walking up the hill each time", you
would be correct. Ultimately the energy comes from the
Sun via the usual light --> biology route.

For the iron cube and magnet, energy comes from you
pulling the cube away from the magnet at the end of
each run, restoring the cube's potential energy.


.

Relevant Pages

  • Re: My dumb experiment with magnets
    ... A cube of iron / steel is placed on the board surface away from the magnet. ... Since there was movement of the iron cube by the magnetic force, ... work and heat were generated which requires energy. ...
    (sci.physics)
  • Re: My dumb experiment with magnets
    ... As the cube is pushed toward the magnet by a person, ... work and heat were generated which requires energy. ...
    (sci.physics)
  • Magnetic Fridge
    ... The solid-state fridge could halve your energy bills and help to save the environment ... The newly-acquired heat - a boost of between 2-5C, ... Magnetocaloric effects are becoming more practical, he thinks, thanks to improved magnet ...
    (sci.energy.hydrogen)
  • Re: My dumb experiment with magnets
    ... A cube of iron / steel is placed on the board surface away from the magnet. ... Since there was movement of the iron cube by the magnetic force, ... work and heat were generated which requires energy. ...
    (sci.physics)
  • Re: My dumb experiment with magnets
    ... what is the source of energy since the cube has not ... been pulled away from the magnet. ... allowed to slide across the board which produced heat. ...
    (sci.physics)