Air at 105 kpa and 37°c flows upward through a 6-cm-diameter inclined duct at a rate of 65 l/s. the duct diameter is then reduced to 4 cm through a reducer. the pressure change across the reducer is measured by a water manometer. the elevation difference between the two points on the pipe where the two arms of the manometer are attached is 0.20 m. determine the differential height between the fluid levels of the two arms of the manometer.