Mechanical Properties Of Fluids Question 6
Question 6 - 2024 (29 Jan Shift 1)
In a test experiment on a model aeroplane in wind tunnel, the flow speeds on the upper and lower surfaces of the wings are $70 \mathrm{~ms}^{-1}$ and $65 \mathrm{~ms}^{-1}$ respectively. If the wing area is $2 \mathrm{~m}^{2}$ the lift of the wing is $\mathrm{N}$.
(Given density of air $=1.2 \mathrm{~kg} \mathrm{~m}^{-3}$ )
Show Answer
Answer: (810)
Solution:
$\mathrm{F}=\frac{1}{2} \rho\left(\mathrm{v}{1}^{2}-\mathrm{v}{2}^{2}\right) \mathrm{A}$
$\mathrm{F}=\frac{1}{2} \times 1.2 \times\left(70^{2}-65^{2}\right) \times 2$
$=810 \mathrm{~N}$
