First of all, hey everyone. I was wondering if any of you could help me solve this. I've tried but i keep getting insane equations so I might be doing something wrong. Two equal spheres with a mass of m have equal charges q. They're suspended by two ropes with length L in points distanced d apart. Calculate the distance between the (centers) of the two spheres when this setup is in balance. Picture: https://dl.dropbox.com/u/29642931/phys.png [Broken] What I've tried so far is: The forces acting on the ball are the electric forces from the charges, the gravity and the tension frmo the rope. I figured the sum of these forces should be 0 for this setup to be balanced, which led me to: Fg + Fel+Frope with |Frope| = |Fg|/cos(θ) + |Fel|/sin(θ), but this is insanely hard to solve..