You shoot an arrow into the air two seconds later 200 s the

Question

Solve the all given parts of following question:

Question: You shoot an arrow into the air. Two seconds later (2.00 s) the arrow has gone straight upward to a height of 26.0m above its launch point.

Part I: What was the arrow's initial speed?

Part II: How long did it take for the arrow to first reach a height of 13.0m above its launch point?

Explain how you came up the prefixes and answer please.