Consider two charged particles. Particle 1 has an electric charge q1=1C and a mass m1=9kg. Particle 2 has a charge q2=8C and a mass m2=9kg. At the beginning, the two particles are at rest separated by a distance D1=1m. Then, you release them and, since they repel each other electrically, they begin to separate due to the electrical force they exert on each other (there are no other forces). You are asked to calculate the speed that particle 1 acquires when both have already moved away at a distance D2=2m.

The answer is 63.21 km/s. I want to know how to get to this answer.