If an arrow is shot straight upward on the moon with a velocity of 56 m/s, its height (in meters) after t seconds is given by $s(t) = 56 t - 0.83 t^2$.
What is the velocity of the arrow (in m/s) after 8 seconds?
After how many seconds will the arrow hit the moon?
With what velocity (in m/s) will the arrow hit the moon?