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: Equilateral triangle net force

  1. Dec 16, 2013 #1
    1. The problem statement, all variables and given/known data

    Lets say I have an equilateral triangle, and you are asked to calculate the net force on the top of the triangle

    2. Relevant equations

    Coulombs Law

    3. The attempt at a solution
    I know to use Coulombs law to find the forces acting on the top of the triangle, then since it is an equilateral triangle, the angle would be 60 degrees and you use that to find the x and y components of the forces acting on the top.
    The x components of the the resultant would cancel out = 0
    The y components would be some number. Then you would just use pythagorean theorem to find the overall net force. However when you find the direction: Tan inverse of Ry/Rx

    Rx would be 0 therefore it is undefined. Does that mean that the direction of the net force on the top of the triangle would be 0 degrees?
  2. jcsd
  3. Dec 16, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Seems like your problem statement is missing some information. Why are you using Coulomb's Law? Are there some unmentioned charges attached to this triangle?
  4. Dec 16, 2013 #3
    Yes there are. The spheres are all negatively charged and have the same charge
  5. Dec 16, 2013 #4
    I used coulombs law because it asked the find the magnitude and direction of the net electric force.
  6. Dec 16, 2013 #5
    And what is the permittivity of the turtle's shell?
  7. Dec 16, 2013 #6
    Ok what?
  8. Dec 16, 2013 #7
    Does anyone have any other input?
  9. Dec 17, 2013 #8
    You have not provided enough information for anyone to understand what you are talking about.

    And see this FAQ.
  10. Dec 17, 2013 #9
    ImageUploadedByPhysics Forums1387281425.397433.jpg

    U use columbs law for a on b and con b , then you draw it out on a Cartesian plane
    Next you find the x and y components of each.
    Then you add them together. The x components cancel out
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted