And please explain what exponent to use on part B please

7. A) Point charges q and Q are positioned as shown in Figure 7. If q = +3.0nC, Q = -8.0nC, a = 3.0m, and b = 4.0m. Compute the electric potentials at points A and B due to the two point charges. How much work is required to move a point charge of 2 MC from point B to A? a q A 90% b a Q O . - B Figure 7: B) Particle-1 has charge of 8 MC and particle-2 has a charge of 40 uC. Each particle has a mass of 0.025 g. If the particles are released from rest with the distance between them equal to 3.0 cm, what is the speed of particle-1 at the instant when the particles are 5.0 m apart