d) A pitot-static tube is used to measure the flow velocity within a subsonic wind tunnel. The total and the static ports of the pitot-static tube are separately connected to the two limbs of a water manometer. If the difference in the water level between the two manometer limbs is 10mm, calculate the air flow velocity in the wind tunnel. The density of air and water are 1.2 kg/m and 1000 kg/m respectively.