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!

Magnitude of the electrostatic force

  1. Sep 6, 2012 #1
    Hello,

    Any help woould be wonderful!

    Identical point charges Q are placed at each of the four corners of a rectangle measuring 2.35 m by 3.05 m. If Q = 26.9 μC, what is the magnitude of the electrostatic force on any one of the charges?


    i dont even know where to start.... HELP!
     
  2. jcsd
  3. Sep 6, 2012 #2

    CAF123

    User Avatar
    Gold Member

    Have you come across Coulomb's Law?[tex] F = k\frac{Q_1Q_2}{r^2} [/tex]
    You need to find the forces acting on any one of the charges. These forces will be from the other 3 charges and because they are identical, the forces acting on your chosen charge will be ones of repulsion.
    You will need to set up a suitable coordinate system. This will allow you to deduce the directions of all force contributions.
     
  4. Sep 6, 2012 #3
    Yes we are learning the law right now. But i am not sure waht to do with the "m" given, do i add them all...? im so lost.
     
  5. Sep 6, 2012 #4

    CAF123

    User Avatar
    Gold Member

    Definitely start by drawing a picture and set the origin of your axes at one of the charges. Then draw in all the forces acting on your chosen charge. Using your coordinate system, write vector equations for each force.
    The 'r' in Coulomb's Law is the distance between two charges. This 'r' will need to be computed using Pythagoras for the charge diagonally opposite the one you chose.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook