Calc help - velocity problem....

[phatmonky]

Just looking to be pointed in the right direction, for now. I understand the equations I have learned about velocity, but am having trouble setting up this word problem:

[quote]If an arrow is shot upward on the moon, with a velocity of 58m/s, it's heigt in meters after t seconds is given by
H=58t-.83t^{2}

Find the velocity of the arrow after one second? (I already figured this out)
Find the velocity of the arrow when t=a?
When will the arrow hit the moon? (I already figured this out)
With what velocity will the arrow hit the moon?

[Tide]

Set H = 0, solve for t then find the corresponding velocity.

Or, since energy is conserved and there is no air resistance then the kinetic energy will be the same at the end of the trajectory as it was at the beginning of the trajectory since the potential energy has a single value at the surface - therefore the speed is the same but the arrow is headed downward.