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Homework Help: Magnetism and mechanical work

  1. Dec 17, 2008 #1

    1. The problem statement, all variables and given/known data
    This is a problem with magnetism and mechanical work.
    Two magnets are facing eachother with opposite poles, where the space between them is called x. The left magnet is beeing hold still, and the right magnet moved. The space between them increases from 2 to 7 cm. Estimate how much mechanical work this movement performs.

    We do also have a table:

    http://dump.no/files/b1c64a658d37/Table.jpg [Broken]

    Basically what's standing there is: "This table shows the relation between F and x"
    Avstand=distance and kraft=force. (Norwegian)

    Link to the picture if it doesn't show up in the thread:
    http://dump.no/files/b1c64a658d37/Table.jpg [Broken]

    2. Relevant equations

    [tex]F=\frac{k1}{x^{2}}[/tex] Where k=Boltzmann's constant

    3. The attempt at a solution
    My attempt on this problem implies integration, because the force is not constant. I integrated [tex]F=\frac{k1}{x^{2}}[/tex] and got [tex]-\frac{1}{{x_B }} + \frac{1}{{x_A }}[/tex], where [tex]x_B[/tex]=2 and [tex]x_A[/tex]=7. I then get [tex]-\frac{5}{{14}}[/tex]. Am I supposed to multiply this with boltzmann's constant? And then put the result I found in the formula for work?

    In advance, thanks for your help!
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Dec 17, 2008 #2


    User Avatar
    Homework Helper

    It looks right. But convert of distance from cm to m. I don't think Boltzmann's constant appears in the magnetic force.
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