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Electrostatics problem (ruddy angles)

  1. Dec 4, 2006 #1
    1. The problem statement, all variables and given/known data
    Calculate the magnitude of the field strength at point P as shown. The distance between the centers of the 1.5E-6 C and the 9.2E-6 C charges is 5.6 cm..

    2. Relevant equations
    E = kq/r^2
    E = F/Q
    E = V/d

    3. The attempt at a solution
    Used tan and sin of 50 to find all distances

    E = kq/r^2
    E = (9E9)(1.5E-6C) / (7.31E-2 m)^2
    E = 2.526E6 N/C

    E = kq/r^2
    E = (9E9)(9.2E-6C) / (4.69E-2 m)^2
    E = 2.526E6 N/C

    then used those numbers to find c^2 using cosine law.

    I'm not getting a correct answer (obvoiusly).


    Attached Files:

  2. jcsd
  3. Dec 4, 2006 #2
    picture is now working
  4. Dec 4, 2006 #3


    User Avatar

    Staff: Mentor

    What's a c^2 cosine law? You have the two vector components of the total E field. Do you know how to add the components? Is the answer expressed in polar or rectangular form?
  5. Dec 4, 2006 #4
    cosine law is:
    c^2 = a^2 + b^2 - 2ab cos c
    I dont know how to add the components or what polar/rectangular form is
  6. Dec 5, 2006 #5


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    Science Advisor
    Homework Helper

    There is no way the fields from the two charges are the same. Your distances look OK.
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