Question

A 25,000 kilogram train is traveling down a track at 20 meters per second. A cow wanders onto the tracks 75 meters ahead of the train, causing the conductor to slam on the brakes. The rain skids to a stop. If the brakes can provide 62,500 Newtons of friction, will the conductor have enough stopping distance to avoid striking the cow?

Answer 1

a = Fap/m = -62,500 / 25,000 = -2.5 m/s^2.

d = (Vf^2-Vo^2)/2a.
d = (0-(20)^2) / -5 = 80 m. = Stopping distance.