Question

A car traveling at 30 m/s north slows to a stop in 15 seconds. What is the acceleration? PLEASE HELP

Answer 1

The answer is C..........

Answer 2

The "acceleration" is negative so it's a deceleration. Change of speed = 30 m/s. Time taken for change 15 seconds Deceleration 30m/s^-1 divided by 15 seconds which is 2m/s per second ...
Nice and gentle, and so not the "modern way"