4. A ferris wheel completes 1 revolution every 18 seconds. At the top, a seat is 16 metres above the ground. At the bottom, it is I'm from the ground. Assume the rider boards the ferris wheel at the bottom of the wheel a) What is the period of the ferris wheel? The amplitude? ( 4 marks) b) What is the radius of the ferris wheel? ( 2 marks) c) How high is the axle above the ground? ( 2 Marks) d) What is the equation of this function? ( 3 Marks)