After 4 seconds, the car in Problem # 2 applies the brakes and comes to a full stop after 2 seconds. What is the acceleration of the car and what is the braking distance?

#2 A car accelerates from rest at 4 m/s^2. What is the velocity of the car after 4 second?

If the car is accelerating uniformly then,

velocity of car at the fourth second is 16m/s

Then if the car with this velocity stopped after 2s then acceleration is,

a=0-16/2=-8m/s^2

braking distance is given by

d=16*2-0.5*8*2*2

=32-16

=16m

this answer is valid only if the motion is one dimensional

all the best.