Answer
$v_{f}$ = 2m/s
d = 0.25m $\approx$ 0.2m " for one significant figure "
Work Step by Step
the maximum speed is the final speed $v_{f}$
$v_{f}$ = a $\times$ t = 0.05 s $\times$ 40 m/$s^{2}$ = 2 m/s
the distance traveled = $\frac{1}{2}$a$t^{2}$ = $\frac{1}{2}$(40 m/$s^{2}$) $\times$ $(0.05s)^{2}$ = 0.25m $\approx$ 0.2m (one signifcant figure)
