A trampoline launches an acrobat straight upward with an initial speed of 4.67 m/s. Taking upward to be the positive direction, (a) (5) find the velocity of the acrobat 0.67 seconds after she is launched. (b) (8) What is the maximum height reach by the acrobat above the trampoline? Assume the trampoline is at y = 0. (c) (7) What is the height of the acrobat above the trampoline 0.90 seconds after she is launched