Question

A car is traveling at 20.8 m/s when the driver sees a dog run out into the street. From the time the driver applies the brakes, it takes 3.58 s for the car to come to a stop. What is the average acceleration during that period?

Answer 1

the velocity changes by -20.8 m/s in 3.58s, for an acceleration of

(-20.8 m/s) / 3.58s = -5.8 m/s^2