A plane is flying from Atlanta to Seattle, approximately 2,150 miles. The plane flies 30 miles beyond Seattle and then is put in a circular holding pattern where he completes one circle every 20 minutes. Let x be the amount of time that has passed and y be the plane's distance from Atlanta. The points are one cycle of the periodic function that models this situation. How long is one period (include units) and what would be the coefficient in front of x in the equation?