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Help with electrostatic force

  1. Oct 27, 2004 #1
    Consider a solid sphere of radius R containing a total charge Q which is uniformly distributed throughout the volume with a volume charge density rho.

    a) find the total force exerted by the electrostatic field on the charge in the 'northern hemisphere'. express your answer in terms of the total charge Q and the radius R of the sphere

    b) evaluate your answer to part a) using R=1m containing 10kg of electrons

    c) find the repulsive force between two sperical volumes of radius R=1m, each containing 10kg of electrons held fixed and separated by a distance of 3000km

    d) by what factor does the magnitude of the repulsive electro. force, found in part c) exceed the gravitational attractive force of the two masses

    e) if the forces holding the two spherical volumes of electrons, fixed at a distance of 3000km, were to vanish, find the initial acceleration that would be experienced by the two 10kg masses. express your answer of units of g-forces of 9.81m per second squared.
  2. jcsd
  3. Oct 28, 2004 #2


    User Avatar
    Science Advisor

    The most straightforward way to sove your problems is to use Maxwell's stress tensor
    to find the appropriate forces. I'm sure I've seen the first problem done in text books, but the specifics escape me.
    Reilly Atkinson
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