Question

The velocity of the wind over the surface of the wing of an aeroplane is `80ms^(-1)` and under the wing `60ms^(-1)`. If the area of the wing is `4m^(2)`, the dynamic lift experienced by the wing is [density of air `=1.3kg.m^(-3)`]
A. 800 N
B. 1000 N
C. 4000 N
D. 3200 N

Answer 1

Correct Answer - C
Pressure difference , `Deltap = DeltaKE = 1/2 xx rho (v_1^2-v_2^2)`
or `Delta = 1/2 xx1.0xx(3600-1600)=1000Nm^(-2)`
`rArr F=(Deltap)xxA = 4000 N`