A \(60 \mathrm{mph}\) wind blows against a football stadium scoreboard that is \(36 \mathrm{ft}\) tall, \(80 \mathrm{ft}\) wide, and \(8 \mathrm{ft}\) thick (parallel to the wind). Estimate the wind force on the scoreboard. See Fig. 9.30 for drag coefficient data.

Fig. 9.30

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Shape D R Square rod with rounded corners R T Rounded equilateral triangle Drag coefficient Reference area A (b = length) D CD = Reynolds number Re = UDI PUA R/D CD 0 2.2 A = bD 0.02 2.0 Re = 105 0.17 1.2 0.33 1.0 R/D CD 0 1.4 2.1 A = bD 0.02 1.2 0.08 1.3 1.9 0.25 1.1 1.3 1231 Re= 105 2.0 D Semicircular shell A = bD 2.3 Re = 2 104 1.1 T Semicircular 2.15 A = bD cylinder 1.15 Re> 104 1.80 T-beam A = bD Re 104 1.65 H I-beam A = bD 2.05 > Re 104 L 1.98 Angle A=bD 1.82 Re> 104 Hexagon A = bD 1.0 Re 104 e/D CD 0.1 1.9 0.5 2.5 A = bD = Rectangle 0.65 2.9 Re 105 1.0 2.2 2.0 1.6 3.0 1.3