A positron is a particle with the same mass as an electron but the opposite charge $(+$e$).$ If a positron is accelerated by a constant electric field of magnitude $301$ N$/$C$,$ find the following. 

 

$($a$)$ Find the acceleration of the positron.

 

$($b$)$ Find the positron's speed after $7\mathrm{.}9010^-\mathrm{⁹}$ s$.$ Assume that the positron started from rest.