Answer :
Area of the wings of the plane, A=2×25=50 m2
Speed of air over the lower wing, V1
=180km/h= 180 x (5/18) = 50 m/s
Speed of air over the upper wing, V2
=234km/h= 234 x (5/18) = 65 m/s
Density of air, =1kg/m3
Pressure of air over the lower wing =P1
Pressure of air over the upper wing =P2
Pressure difference,ΔP = P1−P2 = (1/2) ρ (V22 – V12)
= (1/2) x 1 x (652 – 502) = 862.5 Pa
The net upward force F=ΔP x A
The upward forces balances the weight of the plane
mg = ΔP x A
m = (ΔP x A)/g
= (862.5 x 50)/9.8
=4400kg
The mass of the plane is 4400kg