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!

Point charges

  1. Mar 1, 2007 #1
    Two point charges are separated by a distance r and repel each other with a force F. If their separation is reduced to 0.280 times the original value, what is the magnitude of the force of repulsion between them?


    I don't really understand this question and don't know where to start.
    Would I start with the equation
    E = ((k)(Q)/r^2

    what follows next?
     
  2. jcsd
  3. Mar 1, 2007 #2
    What is the equation for the repulsive force between two point charges, and how does it scale with r?
     
  4. Mar 1, 2007 #3
    It would be Coulomb's law of

    F = ((k)(q1)(q2))/(r^2)

    So it would be -0.280 times the original r value?

    The final answer is 12.8 F but I still don't understand.
     
  5. Mar 1, 2007 #4
    Where do you get the minus sign?

    O.K., you know that F scales as 1/r^2. When r gets smaller, F must get larger. When r is half it's original value, how much larger does F get?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Point charges
  1. Point charges (Replies: 4)

  2. Point charges (Replies: 1)

  3. Point Charges (Replies: 2)

  4. Point charges (Replies: 8)

  5. Point charges (Replies: 4)

Loading...