Question

A driver of a car traveling 14.6 m/s must slam on the brakes to avoid hitting a black bear crossing the road. If it takes 3.00 seconds for the vehicle to slow down to a stop at 0.0 m/s, what is the acceleration over the three seconds?

Answer 1

a = (V2 - V1) / t = (0 - 14.6) / 3 = -4.87 m/s^2

It might be useful to convert 14.6 m/s to mph

14.6 m/s * 39.37 in/m = 575 in /s

575 in/s / 12 in/ft = 47.9 ft/sec

47.9 ft/s / 88 ft/sec * 60 mph = 32.6 mph