In a simplified Bernoulli model of an aeroplane wing, the air speed is 70 m/s over the upper surface and 50 m/s below the wing. The air density is 1.2 kg/m³ and the effective wing area is 25 m². What upward lift is produced by this pressure difference?
Options

Question

In a simplified Bernoulli model of an aeroplane wing, the air speed is 70 m/s over the upper surface and 50 m/s below the wing. The air density is 1.2 kg/m³ and the effective wing area is 25 m². What upward lift is produced by this pressure difference?

Options

G1 Physics · Accepted Answer

At approximately the same height, Bernoulli's equation gives P(lower)−P(upper) = ½ρ[v(upper)²−v(lower)²]. Substitute: ΔP = ½×1.2×(70²−50²) = 0.6×(4900−2500) = 0.6×2400 = 1440 Pa. Lift force is F = ΔP A = 1440×25 = 36000 N = 36 kN. Correct option: C.