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Homework Help: Multiple charges and coulombs law

  1. Dec 3, 2009 #1
    1. The problem statement, all variables and given/known data
    Two negative charges of -1.0 X 10^-6 C are placed in water and separated by a distance of 0.10 m. A positive charge of 1.0 x 10^-8 C is placed exactly midway between the two negative charges.

    a) the electric field( magnitude and direction) and electric potential
    i)at the position of the positive charge
    ii) either negative charge

    b) the electric force( magnitude and direction) experienced
    i) by the positive charge
    ii) by the negative charge

    2. Relevant equations
    E=kq2/Kr2 F=eq1 F=kq1q2/Kr2
    K is electric constant pertaining to material( in this case water) which is 80.4

    W=kq2q1/Kr=Vq1 V=kq2/Kr

    3. The attempt at a solution

    I don't know where to start.:S Any help will be appreciated.
  2. jcsd
  3. Dec 3, 2009 #2
    Hello there;

    Why dont you start with drawing a diagram and placing the charges into positions,

    after you do that consider the E as a vectorial value which affects the charged with the inverse proportional square of radius.So while doing your calculations take note that the values are vectorial not scalar.

    Feel free to write if it still looks complicated;

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