We have been given a = – 6 ms-2,
t = 2s and v = 0
From the equation of motion,
v = u + at
0 = u + (- 6 × 2) .
0 = u – 12
∴ u = 12 ms-1
s = ut + 1/2 at2
= (12 × 2) + 1/2 (- 6 × 2 × 2).
= 24 – 12 = 12m
Thus, the car will move 12 m before it stops after the application of brakes.