A train is at rest at a station. The train then moves away from the station and after 20 seconds, its velocity is 15 m/s and moves at this velocity for 60 seconds. Its velocity increases to 20 m/s over 5 seconds. It moves at a velocity of 20 m/s for 120 seconds and then slows down to come to a stop after a further 30 seconds. a ) During which period was the acceleration of the train the highest?
b) How far did the train train travel during this time?