A 1-m long, thin symmetric airfoil is placed at a free stream. Calculate the drag force for the wind speed of 150 m/s. Assume that the average friction coefficient is C subscript D equals 0.002. A equals 3 space m squared, angle of attack is 0 to the power of degree. A. 81

B. 162 N

C. 40.5 KN

D. 0 N

A (81 N)

Explanation:

P = F/A, where P is the pressure on an object exerted by the force F over the area A. Using "D" to represent drag force specifically, this equation can be rearranged to D = CPA, where C is a constant of proportionality that represents the friction coefficient. The pressure exerted on an object undergoing motion through a fluid can be expressed as (1/2) ρv2, where ρ is the density of the fluid and v is the velocity by which the object is moving. Therefore, D = (1/2) (C) (ρ) (v²) (A).

V = 150 m/s, C (d) = 0.002, A = 3m², ρ (density of air) = 1.2 kg/m3

Fd = (1.2 x 3 x 0.002 x 150²) / 2 = 81 kg. m/s²

The drag force exerted on the airfoil is 81 N.