Solve the all parts of following question given below:
Question: A projectile is launched straight up at 60 m/s from a height of 73 m, at the edge of a sheer cliff. The projectile falls, just missing the cliff and hitting the ground below.
Part I: Find the maximum height of the projectile above the point of firing.
Part II: Find the time it takes to hit the ground at the base of the cliff
Part III: Find its velocity at impact.
Please give a full detailed explanation of answer.