forces acting on a single ball ...
T = tension in the string
mg = weight
F = electrostatic force
let = angle the string makes with the vertical
equilibrium ...
since ...
since ...
Two tiny conducting balls of identical mass m and identical charge q hang from non-conducting threads of length L. Assume that is so small that can be replaced by its approximate equal, .
(a) Show that
gives the equilibrium separation x of the balls.
(b) If L = 120cm, m = 10g, and x =5.0, what is |q|?