A ball is thrown straight down form the top of a 210-foot building with an initial velocity of -18 feet per second. {a} Find the position and velocity functions for the ball. {bl Find the average velocity over the interval [1, 2]. {cl Find the instantaneous velocities when t = 1 and t = 2. {d} How long will it take the ball to hit the ground? {el Find the velocity of the ball when it hits the ground