(12) If an arrow is shot upward on the moon with a velocity of 58 m/s, its height (in meters) after t seconds is given by H = 58t - 0.83t^2.

(a) Find the velocity of the arrow after one second.
(b) Find the velocity of the arrow when t = a.
(c) When will the arrow hit the moon?
(d) With what velocity will the arrow hit the moon?