Posted by Stephanie3 on Friday, July 6, 2012 at 10:34pm.
What must be the distance in meters between point charge q1 = 25.6 µC and point charge q2 = 69.6 µC for the electrostatic force between them to have a magnitude of 8.50 N?

College Physics  Elena, Saturday, July 7, 2012 at 4:15am
k =9•10^9 N•m²/C²
F=k•q1•q2/r²
r=sqrt(k•q1•q2/F)=
=sqrt(9•10^9•25.6•10^6•69.6•120^6/8.5)= .....