8- A 600 m long straight drift airway is being driven on the 1200 m level of an underground mine. The cross section of the airway is the major segment of a circle of radius 9 m wide and its base is 15 m. What will the pressure drop be when 26.0 m3/s of air at 1.2 kg/m3 density flows through the airway? (4 points)