Air flows through a duct, and the Pitot-static tube measuring the velocity is attached to a differential manometer containing water. If the deflection of the manometer is 100 mm, assuming the density of air is constant and equals to 1.22 kg/m3, and that the coefficient of the tube is 0.98. The air velocity will be.
1
0.393 m/s
2
4.07 m/s
3
3.93 m/s
4
39.3 m/s