Question

A fully loaded Boeing air craft has a mass of $3.3 \times 10^{5} kg$. Its total wing area is $500\, m ^{2}$. It is in level flight with a speed of $960\, kmph$. 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, $A=500\, m ^{2}$
The weight of boeing aircraft is balanced by upward force due to the pressure difference.
Hence, $\Delta p \times A=m g$
$\Rightarrow \Delta p=\frac{m g}{A}=\frac{3.3 \times 10^{5} \times 9.8}{500}$
$=6.47 \times 10^{3} \frac{ N }{ m ^{2}} \sim e q 6.5 \times 10^{3} \frac{ N }{ m ^{2}}$