Question

A train moves along a straight track towards a road crossing with a speed of 85.0 km/hr. At the moment the front car of the train arrives at the crossing the conductor applies the brakes which decelerates the train at a constant rate. If the train is 6.00 × 102 m long, and the end of the last
car passes the crossing with a speed of 14.0 km/hr, how long (in minutes) was the train blocking the road at the crossing? You may ignore the width of the crossing.

Answer 1

avg speed=(14+85)/2 km/hr=13.6 m/s
time= distance/velocity=600/13.6 seconds

Answer 2

length = stopping distance = 600 meters
I assume you mean 10^2 = 100
Vi = 85 /3.6 = 23.6 meters/second
average speed during stop = 23.6/2 = 11.8 m/s
time to go 600 meters = 600/11.8 = 50.8 seconds
just under a minute

Answer 3

whoops, sorry, thought it stopped, use Pursley average speed