On Planet X, astronaut Mike Dexter wanted to test how far he could throw a space rock straight up. The function 503) = 1.8 + 491? 7132 models the space rock's height above Planet X's surface in meters t seconds after Mike throws it. a. Determine the equations for the space rock's velocity and acceleration. (5 points) b. What is the space rock's initial velocity (2 points) c. After how many seconds does the space rock reach its maximum height? What is the space rock's maximum height? (5 points) d. At t = 5 seconds is the space rock speeding up or slowing down? Explain your answer. (4 points)