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

Homework Help: Force between two magnets as related to distance

  1. Apr 10, 2008 #1
    I am new to the forum, thus please be patient with me.

    I have a little bit of a problem....

    Currently working with magnets. Basically, I need to derive an equation for the attractive/repulsive force between two magnets given a distance between them. The most important thing is that these magnets not interfere with eachother, in other words I need the attractive/repulsive force to be zero.

    Thoughts so far....
    - Newton's Universal Gravity equation
    - F = GMm/R²
    - manipulate the pull force of the magnet to derive a mass...divide pull force of magnet by 9.8m/s^2
    - need to set F to an infinitely small amount and solve for R

    I do not get offended very easily, so if you need to completely slam my thoughts so far in order to get me on the right track, I understand.

    Thank you in advance for your help
  2. jcsd
  3. Apr 11, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Magnet4less ! Welcome to PF! :smile:

    I'm not sure what you mean … do you mean you want the gravitational attraction between the magnets to be balanced by their magnetic repulsion? :confused:

    (but if so, why are you using the value of g here on Earth?)
  4. Apr 15, 2008 #3
    I'm trying to figure out how close I can place the magnets to one another without them visibly affecting each other.
  5. Apr 19, 2008 #4


    User Avatar
    Science Advisor
    Homework Helper

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook