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Is this diagram wrong? electric potential

  1. Apr 21, 2016 #1
    For the diagram below, is it wrong?
    They have calculated the work done from i to f, using the force that is cross sectional to the particle.
    Shouldn't the force in the direction of the path be the the force x cos theta.
    They have summed the force that is not in the direction of the path?

    Attached Files:

  2. jcsd
  3. Apr 21, 2016 #2
    So the summation should be:

    i to f INT(Q0. E . Cos theta) ds
  4. Apr 21, 2016 #3

    jim hardy

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    Gold Member

    Back to basic math -

    dot product of vectors is not same as dot in algebraic multiplication ?

    doesn't dot product of vectors include cosine of angle between them?

  5. Apr 21, 2016 #4
    Oh yeah thanks.
  6. Apr 22, 2016 #5
    Haha -- dot product of vectors = basic math ... only in PF.
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