Charge Q = 5.00 C is distributed uniformly over the volume of an insulating sphere that has

Charge Q = 5.00 µC is distributed uniformly over the volume of an insulating sphere that has radius R = 12.0 cm. A small sphere with charge q = +3.00 µC and mass 6.00 × 10^-5 kg is projected toward the center of the large sphere from an initial large distance. The large sphere is held at a fixed position and the small sphere can be treated as a point charge. What minimum speed must the small sphere have in order to come within 8.00 cm of the surface of the large sphere?