In Fig. 21-39, two tiny conductingballs of identical mass m and identicalcharge q hang from nonconductingthreads of length L.Assume that u is sosmall that tan u can be replaced by itsapproximate equal, sin u. (a) Show thatgives the equilibrium separation x ofthe balls. (b) If L ! 120 cm, m ! 10 g,and x ! 5.0 cm, what is |q|?