Problem 9.65

กำหนดให้ \(v_{1} = 0 m/s, v_{2} = 30.0 m/s, y_{1} = y_{2} = 0 m,\)

\(A = 225 m^{2}, ρ = 1.20 kg/m^{3}\) และ \(g = 9.80 m/s^{2}\)

จาก\(P_{1}+\frac{1}{2}ρv_{1}^{2}+ρgy_{1}=P_{2}+\frac{1}{2}ρv_{2}^{2}+ρgy_{2}\)

\(P_{1}-P_{2}=\frac{1}{2}ρ(v_{2}^{2}-v_{1}^{2})\)

\(\Delta P=\frac{1}{2}ρ(v_{2}^{2}-v_{1}^{2})\)

\(\Delta PA=\frac{1}{2}ρ(v_{2}^{2}-v_{1}^{2})A\)

\(F=\frac{1}{2}ρ(v_{2}^{2}-v_{1}^{2})A\)

\(F = 0.122 MN \;\blacksquare\)