Question

An airplane wing is designed so that the speed of the air across the top of the wing is 260 m/s when the speed of the air below the wing is 193 m/s. The density of the air is 1.29 kg/m³. What is the lifting force on a wing of area 20.0 m²?

Answer 1

using bernoulli's theoram

P1 + 0.5rho*V1^2 = P2 + 0.5*rho*V2^2

P2 - P1 = 0.5*rho*(V1^2 - V2^2)

Net Upward force on plane wing will be

Force = Pressure difference*Area

F = (P2 - P1)*A

F = 0.5*rho*(V1^2 - V2^2)*A

rho = air density = 1.29 kg/m^3 (Check your reference book and let me know if this value is different)

A = Surface area of wing = 20.0 m^2

V1 = Speed of air above the wings = 260 m/sec

V2 = Speed of air below the wings = 193 m/sec

F = 0.5*1.29*(260^2 - 193^2)*20.0

F = 3.9153*10^5 N

F = Net upward force of air on the plane = 3.92*10^5 N

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