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Electric Field Help

  1. Aug 18, 2014 #1
    Two point charges q1 and q2 are held in place 4.50 cm apart. Another point charge -1.75 mC of mass 4.50 g is initially located 3.00 cm from each of these charges (the figure ) and released from rest. You observe that the initial acceleration of -1.75 mC is 324 m/s^2 upward, parallel to the line connecting the two point charges

    Find q1 and q2 ?

    I attached a pic of my work.

    Attached Files:

  2. jcsd
  3. Aug 18, 2014 #2


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    Hello NickPA. Welcome to PF!

    Your method of solution looks good. But I don't agree with your value of the angle ø. Also, in the problem statement the mass is given as 4.50 g whereas in your calculation you use 5.00 g. In the statement of the problem, Q is given in mC whereas in your calculation you use μC.
  4. Aug 18, 2014 #3
    it is supposed to be 5 g. Bad copy and paste sorry. That seems to be the difference between my answer and the right answer. They (the book authors) are using cos, while i used sin, but should it not work?
  5. Aug 19, 2014 #4


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    I don't see how you got 41.3 degrees for the angle ##\phi## shown in your figure. Can you show your work here?
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