A motorist is traveling at 18.0 m/s when he sees a deer in the road 38.0 m ahead. (a) If the maximum negative acceleartion of the vehicle is -4.50 m/s^2, what is the maximum reation time t of the motorist that will allow him to avoid hitting the deer? thought process... Vf=Vi+at 0m/s=18m/s+(-4.5m/s^2)t t=4 d=Vit+.5at^2 d=18(4)+.5(-4.5)(4)^2 d=36m That means there is 2 meters left for a crash. d=Vit+.5at^2 2=18(t)+.5(0)t^2 t=.11s Max reaction time: .11s (b) If his reaction time is actually .300s, how fast will he be traveling when he hits the deer? .3-.11=.19s the driver goes .19 seconds over 4s-.19s=3.81s how long it takes for him to hit to hit the deer Vf=Vi+at Vf=18m/s+(-4.5m/s^2)(3.18s) Vf=3.69m/s Is this work valid?