Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Laterally moving a magnet

  1. Apr 23, 2016 #1
    According to a magnet manufacturing site, the force required to move a magnet that is attracted to a metal plate laterally away from underneath a magnet is minimal relative to the force required to move it away from the magnet directly away in the opposite direction of pulling force. Assuming the magnets are close but not touching (thus no frictional force between the magnet surface and the metal plate surface), how true is it that the force to move the plate away from the magnet laterally by sliding it left or right (i.e. - the pull force of magnet is up or down) is not really affected by the magnetic force?


    "With a magnet attracting towards a steel plate, there is no lateral force. That’s right, the magnetic force only pulls straight towards the plate, normal to the surface."
  2. jcsd
  3. Apr 23, 2016 #2


    User Avatar
    Gold Member

    You've changed the parameters from the start of you paragraph to the end, from "minimal" to "not really affected". Why is that?

    The title of your thread implies a magnet in lateral motion, I believe your bolded comment is for a stationary magnet, somewhat centered on a plate.
    If the magnet were positioned at the edge of a plate, there would be a lateral force on a stationary magnet.
    There will also be a lateral force if the magnet is moving laterally.
  4. Apr 24, 2016 #3
    For instance...if the magnet is facing upward and pulling downward on the steelplate -- if I pull away the steel plate to the side (left or right) so that the force applied is perpendicular to the direction of the magnet's pull force, is the effort greater than without a magnetic force? I am assuming that the magnets are not touch and thus there is no frictional force between the surfaces of the magnet and the steel plate (just assume there is some magic material between them that prevents touching and is fricitonless)
  5. Apr 24, 2016 #4


    User Avatar
    Gold Member

  6. Apr 24, 2016 #5
    So the upward pulling force of the magnet adds impediments obviously what I am asking is for some kind of guide as to how - my guesses are:

    1. I assumed away friction forces of the surfaces touching - maybe the friction on whatever contraption I use to prevent the surfaces touching?

    2. Some parts of the magnetic field that does not involve a force that is vertical will interfere?
  7. Apr 26, 2016 #6


    User Avatar
    Gold Member

    Just go "textbook", and say there is no friction. Problem solved!
    If the magnet is moving laterally in relation to the steel plate, the changing magnetic field in the plate will induce an electrical current, which will generate a counteractive magnetic field, which will impede the lateral motion of the magnet.

    This can be seen experimentally on the following video from between t=0:56 to t=1:23.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted