Problem 14. A commuter train travels between two stations by accelerating at a rate a for a time t1 and then slowing down with an acceleration of magnitude 5a for

a time t2. The two stations area distance d apart and the train never reaches its maximum speed. The train is at rest at each station. Find the times t1 and t2 in terms of d and a. Additionally, make a qualitatively correct graph of v versus t for the entire process.