As the shuttle bus comes to a sudden stop to avoid hitting a dog, it accelerates uniformly at -4.1 m/s as it slows from 9.0m/s to 0m/s. What is the time needed for the bus stop?

Answer 1

v = at, so t = v/a = (-9.0 m/s) / (-4.1 m/s^2) = 2.195 s

This simple version works only because the bus came to a complete stop.