Solve the all parts of given question:
Question: On a planet in a solar system far from ours, you release a rock from rest at a height of 16 m above the surface of the planet and you find that it takes the rock 3 seconds to reach the surface. Air resistance can be neglected. The mass of the planet is 8 x 1025 kg.
Question I: What is the radius of the planet?
Please show all work and clearly explain. Thank you.