CP A small sphere with mass 1.50 g hangs by a thread between two very large parallel...

CP A small sphere with mass 1.50 g hangs by a thread between two very large parallel vertical plates 5.00 cm apart (Fig. P23.59). The plates are insulating and have uniform surface charge densities +σ and -σ. The charge on the sphere is q = 8.90 X 10^-6 C. What potential difference be-tween the plates will cause the thread to assume an angle of 30.0^o with the vertical?