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!

Find postition on third charge question

  1. Jan 17, 2008 #1
    Find postition of third charge question

    1. The problem statement, all variables and given/known data
    A charge of 1.57E-9 C is placed at the origin, and a charge of 4.23E-9 C is placed at x = 1.51 m. Find the position at which a third charge of 3.11E-9 C can be placed so that the net electrostatic force on it is zero.

    Please help me out with this one


    2. Relevant equations



    3. The attempt at a solution
     
    Last edited: Jan 17, 2008
  2. jcsd
  3. Jan 17, 2008 #2

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    First question: Given that the charges are all positive, and that positive charges repel, do you think the 3rd charge should be placed to the left of both charges, to the right of both charges, or inbetween the two charges? Why?
     
  4. Jan 17, 2008 #3
    i guess it would be at the left of the two charges to counter them..i guess
     
  5. Jan 17, 2008 #4

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Don't guess. Think.

    If the 3rd charge were to the left of the other two, and the other two were both repelling it, then is it even possible that the net force on the 3rd charge is zero? Think about the directions of the forces on the 3rd charge.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?