Two 1.5-cm-diameter disks face each other, 2.0 mm apart. They are charged to ± 9.0 nC.
Part A: What is the electric field strength between the disks? I figured this part out to be 5.8*10^6, which was correct but I really need help with part B!
Part B: A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?