Until a train is a safe distance from the station it must travel at 5 m/s. once the train is on open track it can speed up to 45 m/s. if it takes a train 8 seconds to reach 45 m/s, what is the acceleration of the train? (round your answer to the nearest whole number.) 4 m/s2 5 m/s2 6 m/s2 7 m/s2