**Answer :**

Area of the wings of the plane, A=2×25=50 m^{2}

Speed of air over the lower wing, V_{1}

=180km/h= 180 x (5/18) = 50 m/s

Speed of air over the upper wing, V_{2}

=234km/h= 234 x (5/18) = 65 m/s

Density of air, =1kg/m^{3}

Pressure of air over the lower wing =P_{1}

Pressure of air over the upper wing =P_{2}

Pressure difference,ΔP = P_{1}−P_{2} = (1/2) ρ (V_{2}^{2} – V_{1}^{2})

= (1/2) x 1 x (65^{2} – 50^{2}) = 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