Two particles each have a mass of 6.00 x 10-3 kg. One has a charge of +5.0 x 10-6 C, and the other has a charge of -5.0 10-6 C. They are initially held at rest at a distance of 0.85 m apart. Both are then released and accelerate toward each other. How fast is each particle moving when the separation between them is one-half its initial value?