Mathematics · Fluid Mechanics Calculations

A sphere of 4 cm diameter made of aluminum (specific gravity = 2.8) is suspended by a string in a wind tunnel. An air stream of 80 m/s flows past it. Given air density ρa = 1.2 kg/m3, kinematic viscosity νa = 1.5 × 10-5 m2/s, and drag coefficient CD = 0.2 (since Re > 3 × 105), find the inclination angle θ of the string with the vertical and the tension T in the string. (Take g = 9.81 m/s2)