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Homework Help: Electriccal charges and vectors

  1. Mar 14, 2005 #1
    Code (Text):
    +q    -a-    -q

    |            |
    a            a
    |            |

    +2q   -a-  -2q
    What are the horizontal and vertical components of the resultant electrostatic force on the charge in the lower left corner of the square if q = 0.9 10-7 C and a = 4.4 cm? (Assume the positive directions are upward and to the right.)

    For the horizontal component I got .0013081 N and for the Vertical I got 4.321 N, but neither one is correct.

    I found the charge between +2q and -2q, and then I added the charge from +2q to -q times cos(45). That should have given me the horizontal charge but it didn't. What am I doing wrong?
  2. jcsd
  3. Mar 14, 2005 #2
    your answer for the horizontal component is a factor of 2 off (that is my answer is twice the value of your answer), did you account for the 2q?

    edit: if show your equations we can see exactly where an error occured
  4. Mar 14, 2005 #3
    If your answer is .0026162 N that isn't correct either. I don't really know how to show the calculations here though.
  5. Mar 15, 2005 #4
    The exact answer I got was .026626077 N, which is assuming that the positive direction is to the right. What does the book say the correct answer is?
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