Question

A fully loaded Boeing air craft has a mass of $3.3\times 10^{5}kg$. Its total wing area is $500m^2$. It is in level flight with a speed of $960kmph$. Estimate the pressure difference between the lower and upper surfaces of the wings.

• A. $4.5\times 10^{3}N\cdot m^{-2}$
• B. $5.5\times 10^{3}N\cdot m^{-2}$
• C. $6.5\times 10^{3}N\cdot m^{-2}$
• D. $7.5\times 10^{3}N\cdot m^{-2}$

Answer 1

Answer: (C)

Mass of boeing air craft,
$M=3.3\times 10^{5}kg$
Wing's area, $A=500m^2$
The weight of boeing aircraft is balanced by upward force due to the pressure difference.
Hence, $\Delta p\times A=mg$
$\Rightarrow \Delta p=\frac{mg}{A}=\frac{3.3\times 10^5\times 9.8}{500}$
$=6.47\times 10^3\frac{N}{m^2}\sim eq6.5\times 10^3\frac{N}{m^2}$