A car is travelling at a speed of 13 m/s. The driver applies the brakes and the car comes to rest after travelling a further 26 m. What is the deceleration of the car in m/s^2?

Answer 1

Vi = initial speed
v = Vi + a t
easy way to get time is use average speed during constant acceleration
Vaverage = Va = (13+0) /2 = 6.5 m/s
so time to stop = t = 26 / 6.5 = 4 seconds
so
0 = 13 + a (4)
a = -13/4 m/s^2