1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Charges problem.

  1. Jan 27, 2004 #1
    Four charges are arranged in (x,y) plane:
    -3nC at (-4, 1)
    -4nC at (0, 0)
    -6nC at (5, 3)
    -7nC at (4, 5)

    Find the magnitude of the resulting force charge at the origin(0, 0).

    I know how to find radius:
    R1(squared) = 17
    R2(squared) = 0
    R3(squared) = 34
    R4(squared) = 41

    But I don't know which charges to use in the equation to find four different forces:
    K = 8.99 * 10^9

    Can someone please help me?
  2. jcsd
  3. Jan 27, 2004 #2
    Find the field at the origin by other charges exluding the one which is placed at the origin(* NOTE *) Add vectorially
  4. Jan 27, 2004 #3
    posted the question wrong

    Find the magnitude of the resulting force on the -4nC charge at the origin.

    And radius' are suppose to be from that charge, so they are only 3 radius.
  5. Jan 27, 2004 #4
    Yes , but F is vector u can not add only magnitudes it has to be done in proper manner
  6. Jan 27, 2004 #5
    Tell me if I'm doing this right, I'm getting big numbers thta's why I have a doubt:

    F1 = 8.99e9*4e-9*3e-9/17 = 6.346e-9
    F2 = 8.99e9*4e-9*6e-9/34 = 6.346e-9
    F3 = 8.99e9*4e-9*5e-9/41 = 4.385e-9

    Ang1= tan^-1(1/-4) = -14.04
    Ang2= tan^-1(3/5) = 30.96
    Ang3= tan^-1(5/4) = 51.3

    Am I right so far?
  7. Jan 27, 2004 #6
    Let the forces be in form Kq1q2/r^2

    Yes angles are correct but what are the directions of these vectors??

    After finding the direction resolve the components along x&y axis And now add the components
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Charges problem.
  1. Charge problem (Replies: 6)

  2. Charge problem (Replies: 2)