4. a subsonic wind tunnel with an area ratio of 1/6 is operating at standard sea level conditions. a. if the test section speed is 44 ft/s, what is the pressure difference between the settling chamber and the test section? b. if the pressure in the settling chamber is 2000 lb/ft2, what is the pressure in the test section? c. the exit of the diffuser has an area that is 7 times the size of the test section. what is the velocity at the exit of the diffuser? d. what is the pressure at the exit of the diffuser?