17. An object is thrown straight up with a velocity, in ft/s, given by v(t) = -32t + 64, where t is in seconds, from a height of 48 feet:
(a) What is the object's maximum velocity?
(b) What is the object's maximum displacement?
(c) When does the maximum displacement occur?
(d) When will the object reach a height of 0? (Hint: find when the displacement is -48ft.)