A cylindrical air duct in an air conditioning system has a length of 3.5 m and a radius of 5.00 10-2 m. A fan forces air (ç = 1.8 1 x0-5 Pa·s) through the duct, such that the air in a room (volume = 242 m3) is replenished every 12 minutes. Determine the difference in pressure between the ends of the air duct.