When measuring small pressure differences with a manometer, often one arm of the manometer is inclined to improve the accuracy of the reading. (The pressure difference is still proportional to the vertical distance, and not the actual length of the fluid along the tube.) The air pressure in circular duct is to be measured using a manometer whose open arm is inclined 450 from the horizontal, as shown in the figure. The density of the liquid in the manometer is 0.81 Kg/L, and the vertical distance between the fluid levels in the two arms of the manometer is 12 cm. Determine a. the gage pressure of air in the duct. b. the length of the fluid column in the inclined arm above the fluid level in the vertical arm. [17 cm]

Fig: 1

Fig: 2

Fig: 3