The resultant of the pressure and wall shear forces acting on a body is measured to be 470 N, making 33° with the direction of flow. Determine the drag and the lift forces acting on the body.

The jet plane in Fig. 6–19a is in level flight with a constant speed of 140 m/s. Each of its two turbojet engines burns fuel at a rate of 3 kg/s. Air, at a temperature of 15°C, enters the intake, which has a cross- sectional area of 0.15 m². If the exhaust has a velocity of 700 m/s, mea- sured relative to the plane, determine the drag acting on the plane. W 140 m/s FD O O O OO O O Oo O (a) (b)

The resultant of the pressure and wall shear forces acting on a body is measured to be 430 N, making 30° with the direction of flow. Determine the drag and the lift forces acting on the body.

B2 is flying at an altitude of 43,000 ft and a speed of 400 KTAS under standard atmospheric conditions. If the average aerodynamic chord is 39,6 ft, calculate the Reynolds number and the average % aerodynamic chord present on the wing

Choose the most appropriate statement with respect to the pressure distribution of an airfoil. The flow velocities go to zero at the leading and trailing edge points. Upper and lower surface pressures are lower than under free-stream conditions. Upper and lower surface pressures are higher than under free-stream conditions. O Lift is the difference between the lower and upper surface pressures.

6 The fins on the radiator of your car are about 2 in long. When your car is going 60 mi/h, the free-stream velocity of the air approaching these fins (under the hood of the car and behind the grille) is estimated to be 40 mi/h. Estimate the boundary layer thickness at the downstream end of the fins.

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Large commercial airplanes cruise at high altitudes (up to about 40,000 ft) to save fuel. Discuss how flying at high altitudes reduces drag and saves fuel. Also discuss why small planes fly at relatively low altitudes.

Air is flowing past a spherical ball. Is the lift exerted on the ball zero or nonzero? Answer the same question if the ball is spinning.

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