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Homework Help: Pull Force of a Permanent Magnet at a Certain Distance

  1. May 13, 2010 #1
    1. The problem statement, all variables and given/known data
    What would be the necessary magnetic field strength needed to pick up a 0.1543 lb. magnetic object 0.238 meters away? (I am trying to find a permanent magnet, not an electromagnet to accomplish this)
    (the pull force of the permanent magnet I am using is 4.7 lb)

    2. Relevant equations
    For a circular magnet with a radius of R and Length L, the field at the centerline of the magnet a distance X from the surface can be calculated by the following formula (where Br is the Residual Induction of the material)

    3. The attempt at a solution
    I chose a small neodymium magnet and found the magnetic field strength at 0.238 meters away to be 5.6587 [tex]\mu[/tex]T. The problem is that I do not know if that is enough to pick up the 0.1543 lb. object.

    Perhaps there is an equation relating pull force of a permanent magnet to the distance of the object?

    Attached Files:

  2. jcsd
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