Question

A jet airplane in level flight has a mass of 8.61 x 104 kg, and the two wings have an estimated total area of 88.0 m2 (a) What is the pressure difference between the lower and upper surfaces of the wings? Pa (b) If the speed of air under the wings is 233 m/s, what is the speed of the air over the wings? Assume air has a density of 1.29 kg/m3 m/s (c) Explain why all aircraft have a "ceiling," a maximum operational altitude The density of air ..Select with increasing height, resulting in aSelect. longer support the aircraft. pressure difference. Beyond the maximum operational altitude, the pressure difference can no Need Help?Read It 2 points SerCP11 9.P.044 A large storage tank, open to the atmosphere at the top and filled with water, develops a small hole in its side at a point 18.2 m below the water level. If the rate of flow from the leak is 2.30 x 10-3 m3/min, determine the following My Notes Ask Your Tea (a) Determine the speed at which the water leaves the hole m/s (b) Determine the diameter of the hole.

Answer 1

a) Assuming the airplane is in level flight, The net libt (the difference in the upward and downward forces exerted on the wings by the air following over then) must equal the weight of the plane (p_lower surface - p_upper surface)A_weight = mg p_lower surface - p_upper surface = mg/A_wings = 8.61 times 10^4 times 9.8/88m^2 = 9588.40pa b) Applying Bernoullis equation. p_lower + 1/2 p_air V^2_power = p_upper + 1/2 p_air V^2_upper V^2_upper = V^2_lower + 2(p_lower - p_upper)/p_air = (233)^2 + 2(9588.40)/1.29 = 54289 + 14865.73 = 69154.73 V_upper = 262.97m/sec. \r\n c) The density of air decrease with increasing height, resulting in a smaller pressure difference Delta P = 1/2 p_air [v^2_upper - v^2_lower] Beyond the maximum operational altitude The pressure difference can be longer support the aircraft. a) Speed v = squareroot 2gh = squareroot 2 times 9.8 times 18.2 = 18.88m/sec. b) volume flow V = AV V = 2.30 times 10^-3 m^3/min