1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Magnetic force lost when you break a magnet?

  1. Oct 24, 2012 #1
    if you have a magnet that pulls 40lbs of force if you broke that into 2 how much force will each magnet pull.

    i have some neodymium magnets from hardrives and i wanna break them up but i wanna know if thats gunna make them lose alot of force. anyone know the formula for calculating such a thing? or better yet just plane old english will work lol. thanks
  2. jcsd
  3. Oct 24, 2012 #2
    if you break it in two equal parts they will pull 20 lbs every one
  4. Oct 25, 2012 #3

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    It depends how you break them. If you bereak them like this |S_________|__________N|,
    you will get two magnets with the same 40 pounds. Breaking then along the length, would give two magnets of 20 pounds. For a given magnetization, the force is proportional to the area of the (N or S ) end of the magnet.
  5. Oct 25, 2012 #4
    I'm not at all sure that breaking a modern magnet in half will give you something like 50:50.

    I would guess that's true of an old steel magnet but modern crystalline high-power magnets are much more sophisticated and might react badly to being fractured.

    Anyway, it would be interesting to find out.
  6. Oct 25, 2012 #5


    User Avatar
    Science Advisor

    Maybe you will gain some force, since 2 magnets can be placed closer to the surface than 1 big magnet. Why don't you try it out and tell us the result?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook