Question

14 48 of an outer tube with a number of 48 A pitot tube (Fig. 14-41) is used to determine speed of an airplane. It consists of an outer tube with a numo small holes B (four are shown that allow air into the tube, tube is connected to one arm of a U-tube. The other arm of the U- tube is connected to hole A at the front end of the device, which points in the direction the plane is headed. At A the air becomes stagnant so that VA = 0. At B, however, the speed of the air pre- sumably equals the airspeed y of the plane. (a) Use Bernoulli's equation to show that = 2pgh V Pair where p is the density of the liquid in the U-tube and h is the differ- ence in the liquid levels in that tube. (b) Suppose that the tube con- tains alcohol and the level difference h is 26.0 cm. What is the plane's speed relative to the air? The density of the air is 1.03 kg/m and that of alcohol is 810 kg/m². Pair Hole A- Liquid Figure 14-41 Problems 48 and 49. 14-49 A pitot tube (see Problem 48) on a high-altitude aircraft measures a differential pressure of 150 Pa. What is the air airspeed if the density of the air is 0.031 kg/m2

Answer 1

Bernoul fuha P , , 2 4P frewure AP = 2 2 2-76 V- 2 41 /50 Pa G=ap= 2 x150 98. 37 de 0.031 1l