An athlete is training on a 100 m long linear track. His motion is described by the graph of his position vs. time, below. On a coordinate plane the horizontal axis is labeled t (s) and the vertical axis is labeled x (m). There are four connected line segments labeled A, B, C, and D. Segment A begins at (0, 0) and rises up and to the right passing through (5, 30) to reach (10, 60). Segment B begins at (10, 60) and continues horizontally to end at (30, 60). Segment C begins at (30, 60) and drops down and to the right to end at the point (45, 40). Segment D begins at the point (45, 40) and continues up and to the right passing through the points (50, 60) and (55, 80) to end at the point (60, 100). (a) For each segment of the graph, find the magnitude and direction of the athlete's velocity. magnitude vA m/s direction vA ---Select--- magnitude vB m/s direction vB ---Select--- magnitude vC m/s direction vC ---Select--- magnitude vD m/s direction vD ---Select--- (b) What are the magnitude and direction of the athlete's average velocity over the entire 60 s interval? magnitude m/s direction ---Select---