30. (C)
The velocity is graphed in [−1,11] × [−15, 5]. The object reverses direction when the
velocity changes sign, that is, when the graph crosses the x-axis. There are two such
reversals − at x = a and at x = b.
The velocity is graphed in [−1,11] × [−15, 5]. The object reverses direction when the
velocity changes sign, that is, when the graph crosses the x-axis. There are two such
reversals − at x = a and at x = b.