1. Not finding help here? Sign up for a free 30min 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!

Force on Magnetic Dipole

  1. May 3, 2013 #1
    1. The problem statement, all variables and given/known data
    71n13p.png


    2. Relevant equations



    3. The attempt at a solution

    I found dB/dr to be constant near r = 0, so it's a straight line, implying B increases linearly with r near r = 0.

    For the second part, I assume the setup is as such, if not placing the dipole with its axis parallel to the coil would make B = 0, and hence no force at all..Not sure what energy has to do in this case.

    119zcrb.png
     
  2. jcsd
  3. May 3, 2013 #2
    There is a relationship between potential energy and force.
     
  4. May 3, 2013 #3

    TSny

    User Avatar
    Homework Helper
    Gold Member

    Sounds good.

    [Edited to correct a misstatement] Although there is only an r-component of field on the axis of the Maxwell loops (r-axis), off the axis there will be a radially inward field (perpendicular to the r-axis and toward the r-axis). A dipole in the form of a small current loop would experience a force due to this radially inward field.

    But, it's easier to find the force by using the idea that force is the negative gradient of potential energy: F = -∇E. See if you can use this to find the force. [I see MisterX posted this suggestion before me. Sorry.]
     
    Last edited: May 3, 2013
  5. May 5, 2013 #4
    Then, wouldn't the force simply be F = - ∂U/∂r = m ∂Bext/∂r at r = 0?

    This is simply the earlier part of the question of finding ∂B/∂r at r = 0.
     
  6. May 5, 2013 #5

    TSny

    User Avatar
    Homework Helper
    Gold Member

    Yes, that's right.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Force on Magnetic Dipole
  1. Force on a dipole (Replies: 5)

  2. Magnetic Dipole (Replies: 1)

Loading...