As you ride a Ferris wheel, the height that you are above the ground varies periodically. Consider the height of the center of the wheel to be the equilibrium point. A particular wheel has a diameter of 38 feet and travels at a rate of 4 revolutions per minute.

a) Write an equation to describe the changes in height, h, of the seat that was filled last before the ride began in terms of time, t, in seconds. The seat was at the minimum height at t = 0.

b) Find the height of the seat after 22 seconds.

c) If the seats of the Ferris wheel clear the ground by 3 feet, how long after the ride starts will the seat be 27 feet above the ground?