Starting at one station, a subway train accelerates from rest at a constant rate of 1.0 m/s² for half the distance to the next station, then slows down at the same rate for the second half of the journey. The total distance between stations is 900 m. 

(a) Sketch a graph of the velocity v as a function of time over the full journey. 

(b) Sketch a graph of the distance covered as a function of time over the full journey. Place appropriate numerical values along both axes.