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?

(a) $v(1) =$ m/s
(b) $v(a) =$ m/s
(c) $t =$ seconds
(d) m/s