A piece of rock is falling from a height of exactly 1,200 meters to a planet, the gravitational acceleration of the planet is 21.5 m/s^2, the rock also have an air deceleration of -2.5 m/s^2 per 10 m/s velocity, answer the following questions:
1.The speed of the rock when it hits the ground?
2.The terminal velocity of the planet?
