A ball is thrown straight up from a 20 m cliff above the ground level with a speed of 15. On the way down it misses the cliff and continues down to the ground level. The trajectory of the ball is shown as a dashed line in the figure. The free-fall acceleration has a magnitude of 10 and is directed downwards. A. Given this trajectory, what is the net displacement of the ball? Assume that the positive y-direction points up, as shown in the figure. B. Find the total time the ball is in the air. Express your answer in seconds. 0 y (m) 20 27 C. Calculate the ball's velocity in the y-direction v, exactly 4 seconds after it is thrown up. Use the usual sign convention (positive for up, negative for down). Express your answer in m/s.