Posted by Anonymous on .
What is the net upward force on an airplane wing of area 20.1 m2 if the speed of air flow is 302 m/s across the top of the wing and 287 m/s across the bottom? (assume the density of air is 1.29 kg/m3)

physics 
MathMate,
Using Bernoulli equation:
P+(1/2)ρV²+ρgh=constant.
We get
P1+(1/2)ρV1²=P2+(1/2)ρV2²
ρgh being constant.
Thus
P2P1=(1/2)ρ(V1²V2²)
=(1.293*g)*(302²287²)
=111,952 N/m²
The net upward lift
=111,952*20.1 N/m² m²
=2.25*10^{6} N
Compare with the weight of a Boeing 7478:
442,000 Kg= 4.33*10^{6} N.