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: Determing charge

  1. Feb 3, 2012 #1
    Objects A and B are both positively charged. Both have a mass of 100 g but A has twice the charge of B. When A and B are placed with 10 cm between their centers, B experiences an electric force of 0.35 N

    What is the charge of qa?

    I have no idea where to start... I know of the equation..

    F = k|q*q'|/r^2
    but this does not relate to mass in any way... so how am I suppose to implement the 100g into the equation to solve for qa?
  2. jcsd
  3. Feb 3, 2012 #2


    User Avatar

    Staff: Mentor

    For this part of the problem, I believe the mass is irrelevant. There may be a follow-on question that asks for the acceleration due to the electric forces or something...
  4. Feb 3, 2012 #3
    the follow up question is what is the charge of B
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook