If an arrow is shot upward on the moon with velocity of $26$ m/s, its height (in meters) after $t$ seconds is given by $$h(t) = 26 t - 0.83 t^2.$$

(a) Find the velocity of the arrow after $7$ seconds.

Velocity = m/s
(b) Find the velocity of the arrow after $a$ seconds.

Velocity = m/s
(c) When will the arrow hit the moon?

Time = s
(d) With what velocity will the arrow hit the moon?

Velocity = m/s