A red train traveling at 65 km/h and a green train traveling at 143 km/h are headed toward one another along a straight, level track.

A red train traveling at 65 km/h and a green train traveling at 143 km/h are headed toward one another along a straight, level track. When they are 910 m apart, each engineer sees the other's train and applies the brakes. The brakes slow each train at the rate of 1.0 m/s2.