The motion of a ball is modelled by the functions x(t) = 4t, y(t) = -4.9t2 + 20t+2 Where x(t) is the horizontal distance and y(t) is the height above the ground (both in meters) and t is time in seconds. a ) What is the initial velocity of the ball? Write your answer in vector notation. b ) Compute the maximum height of the ball. c ) Compute the time when the ball hits the ground and the horizontal distance from its starting point when it hits the ground. day d2 x d) Interpret dt 2 and dt2