Two $2\mathrm{.}0$ cm diameter disks face each other, $1\mathrm{.}0$ mm apart. They are charge to $10$ nC$.($a$)$ What is the

electric field strength between the disks? $($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? $($ANS:

$3\mathrm{.}6106$ N C$,8\mathrm{.}3105$ m s$)$