A rocket blasts off vertically from rest on the launch pad

Question

Compute all parts of given question:

Question: A rocket blasts off vertically from rest on the launch pad with an upward acceleration of 2.90 m/s². At 20.0s after blastoff, the engines suddenly fail, which means that the force they produce instantly stops.

Part I: How high above the launch pad will the rocket eventually go?

Part II: Find the rocket's velocity at its highest point.

Part III: Find the magnitude of the rocket's acceleration at its highest point.

Part IV: Find the direction of the rocket's acceleration at its highest point.

Part V: How long after it was launched will the rocket fall back to the launch pad?

Part VI: How fast will it be moving when it does so?

Please explain your answer. I know substitution is involved so be sure to give a detailed explanation on that as well.