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What kind of physical force does the earth's magnetic field exert on any object?

  1. Apr 17, 2009 #1
    Firstly let me waste a bit of your time by explaining I have not done much with maths or physics for ages! So please forgive my stupidity.

    My question:
    What kind of physical force does the earth's magnetic field exert on any object on earth?

    My calculations (very probably deeply flawed):
    Google says the earth's magnetic field is 0.3 - 0.7 Gauss in strength.
    This is equal to 0.00003 - 0.00007 Tesla
    T= 1(N/A*m)

    I assumed:
    N = newton
    A = Area / surface in m2
    m = mass of the (magnetic?) body(?) in kg

    So the force on an object (weight: 1kg / contact area with ground: 1m2) would be:

    T = N = 0.00003 - 0.00007 Newton

    Now after someone has pounded my math into dust I still wonder if this only applies to a place on earth where the magnetic field lines are at a 90 degree angle with the earth's surface? And what would apply for a place around the equator for example?

    Any comments are welcome.
  2. jcsd
  3. Apr 17, 2009 #2


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    Gold Member

    Nope, it is Newton per Ampere - meter. See http://en.wikipedia.org/wiki/Tesla_(unit [Broken])
    Last edited by a moderator: May 4, 2017
  4. Apr 17, 2009 #3
    The Earth's magnetic field produces only torques on magnets like compass needles, because the compass needle is a magnetic dipole, equivalent to a magnetic monopole at each end. If we had any free monopoles around, they would be pulled to either the North pole (near Greenland) or the South pole (near Antartica).
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