The following data describe different situations where a person is walking or running through a train car while the train is in motion. The speed and direction of motion of the person (P) and the train (T) are given in each case, with east being reckoned as positive, west as negative. An observer is standing beside the track watching the train and its occupant pass by. Rank these situations on the basis of the velocity of the walkers/runners with respect to the stationary observer outside the train from largest to smallest. If any of the walkers/runners have the same velocity, give them the same ranking.
(a) P: 2 m/s, west; T: 20 m/s, east
(b) P: 6 m/s, east; T: 30 m/s, west
(c) P: 4 m/s, west; T: 30 m/s, west
(d) P: 10 m/s, west; T: 10 m/s, east
(e) P: 2 m/s, east; T: 20 m/s, west
(f) P: 4 m/s, east; T: 25 m/s, east