What net force speeds up a 1200 kg car from rest to 20 m/s in 8 s?

Newton's second law: $F = ma$, where $F$ is the net force. Plan: draw the forces, find the net force, use $a = F/m$, then the equations of motion ($v = u + at$, $s = ut + \tfrac12 at^2$, $v^2 = u^2 + 2as$).