If a car at rest accelerates uniformly to

Here $v = 144\;km/h = 40\,m/s$

$v = u + at$ 

$⇒$ $40 = 0 + 20 \times a \Rightarrow a = 2\;m/{s^2}$

$\therefore s = \frac{1}{2}a{t^2} = \frac{1}{2} \times 2 \times {(20)^2} = 400\;m$