Acar travelling at 45 mi/hr (20.1 m/s) comes to rest in 4 seconds. find the acceleration of the car in m/s2.

         Acceleration = (change in speed) / (time for the change)

Change in speed = (speed at the end) minus (speed at the beginning)

                                   (0  -  20.1 m/s)  =  - 20.1 m/s

Time for the change = 4 sec

Acceleration = (-20.1 m/s) / (4 sec) = -5.025 m/s²

Your answer is 32 hope i