1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: About coulomb's law

  1. Aug 4, 2004 #1
    Dear all...

    i have a question about coulomb's law as follows:

    if there are three point charges are placed at the x-axis, first is +C, second is -C and the last one also is -C.

    How could i know the direction of the force at the second and third one ??

    best regards.

  2. jcsd
  3. Aug 4, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You'll have to be more specific: where are the charges? I assume you need to find the forces that these charges exert on each other? Remember that like charges (same sign) repel and unlike charges attract.
  4. Aug 4, 2004 #3
    Dear Doc Al

    what is meaning of repel ??

    if there is two postive charge at the X axis, one is 5C at x = 0, other is 6C at x = 40,
    so what is the force direction ?? positve or negative ??


  5. Aug 4, 2004 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Repel means push away. Attract means pull together.
    I assume you are talking about the forces they exert on each other?
    Since these charges are both positive, they will repel each other. So:
    (1) the force on the 5C charge at x = 0 will point in the negative x direction
    (2) the force on the 6C charge at x = 40 will point in the positive x direction

    Make sense?
  6. Aug 4, 2004 #5
    thanks a lot !!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook