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Homework Help: Electrostatic field

  1. Apr 8, 2015 #1
    1. The problem statement, all variables and given/known data
    Can someone confirm if I answered correctly?

    Question: Two small identical spheres each carrying a charge, +q C, are placed on the line LM as shown in the diagram:
    Describe how the intensity and direction of the electric field produced by the two charges varies:
    i) Along the line LM, and
    ii) Along the line AB

    b) Describe how the acceleration and velocity of a positively charged particle initially at rest on the line LM very close to one of the charges +q, changes as the particle moves away from the charge.
    2. Relevant equations

    3. The attempt at a solution
    i) Since the charges are both positive there will be a repulsion and the electric field along LM will be vacant.
    ii) As for the direction same applies since both of the fields collide, no fields will be present along line AB since it is positioned between the two spheres.

    b) The velocity would change due to a decrease in potential energy, as the other charge moves away the distance r begins to increase. When r=infinity the potential energy would be equal to zero. P.E=K.E

    As for the acceleration, since the mass is a constant the force between the two charges would decrease.
  2. jcsd
  3. Apr 8, 2015 #2


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    Vacant meaning zero ? No.

    Again. No. Both fields will be present. The term "collide" isn't applicable to fields in this stage of your education. The fields are static.

    It says "Initially at rest". With "other charge" you mean the particle ? With "distance r" you mean what, exactly ? Do you realize X is also on the line LM ?

    Which two charges, exactly ? There are three of them in this story...

    PS the section 2. Relevant eqations is blank on my screen. But you do need equations for the filed. make sure they are correct and complete when you post them.
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