Consider an elevator in a tall building. The elevator is initially at rest on a floor that is neither the highest nor lowest floor, At time t = 0, the doors of the elevator begin to close. The acceleration of the elevator from time
= 0 to time - 25 seconds is shown in the graph above. Let the positive direction be upward.
(a)
Is the elevator moving upward, moving downward, or at rest at time t = 12 seconds? If the elevator is
moving, state its speed. In any case, explain your reasoning.
(b)
Is the elevator moving upward, moving downward, or at rest at time t = 22 seconds? If the elevator is
moving, state its speed. In any case, explain your reasoning.