Three point charges are arranged along the x-axis. Charge q1 = +3.00 uC is at the origin, and charge q2= -5.00 uC is at x= 0.200 . Charge q3= -8.00 uC.
Where is q3 located if the net force on q1 is 7.00 N in the -x direction?

Question

jamesj · Answer

Use Coulomb's law to find the force on q1 from q2--call it $  F_{12} $ and the force of q3 on q1--call it $ F_{13} $, by writing the q3 is at some arbitrary point x.

You know the sum $ F_{12} + F_{13} = 7.00 \ Newtons $ and you will now have an equation involving only one variable: x.  Solve that equation.

anonymous · Answer

yeah whatever jamesj said was right but i just wanna make it more simpler
 F13 - F12=7.00 . So that you would not have to worry about the direction of forces.