A rock is thrown straight up from a 30 m cliff above the ground level with a speed of 20. On the way down it misses the cliff and continues all the way down to the ground level. The trajectory of the rock is shown by the black dashed line in the figure. The free-fall acceleration has a magnitude of 10 and is directed downwards. A. What is the net displacement of the rock for its entire trajectory? Assume that the positive y-direction points up, as shown in the figure. B. Find the total time the rock is in the air. Express your answer in seconds. 30 C. Find the rock's velocity in the y-direction v exactly 5 seconds after it is thrown up. Use the usual sign convention (positive for up, negative for down). Express your answer in m/s. D. Plot the rock's velocity in the y-direction v, for the first 5 seconds after it is thrown up. Label relevant values on the vertical axis. E. What feature of your graph shows that the acceleration is constant, and what feature of your graph shows that the acceleration points downward? v,, (m/s) 2 3 S t (s)