Air is streaming past a horizontal airplane wing such that its speed is $120 \ m/s$ over the upper surface and $90 \ m/s$ at the lower surface. If the density of air is $1.3 \ kg/m^3$ and the wing is $10 \ m$ long and has an average width of $2 \ m$,then the difference of the pressure on the two sides of the wing is ....... $Pascal$.

Water is flowing through a horizontal pipe of non-uniform cross-section. In the region of the narrowest part inside the pipe,the water will have

The weight of an aeroplane flying in air is balanced by

Consider a completely full cylindrical water tank of height $1.6 \ m$ and cross-sectional area $0.5 \ m^2$. It has a small hole in its side at a height $90 \ cm$ from the bottom. Assume the cross-sectional area of the hole to be negligibly small as compared to that of the water tank. If a load of $50 \ kg$ is applied at the top surface of the water in the tank,then the velocity of the water coming out at the instant when the hole is opened is ......... $m/s$ $(g=10 \ m/s^2)$.

$A$ fully loaded Boeing aircraft 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 $960 \; km/h$.
$(a)$ Estimate the pressure difference between the lower and upper surfaces of the wings.
$(b)$ Estimate the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface. [The density of air is $\rho = 1.2 \; kg/m^{3}$]

$A$ liquid flows through a horizontal tube. The velocities of the liquid in the two sections which have areas of cross-section $A_1$ and $A_2$ are $v_1$ and $v_2$ respectively. The difference in the levels of the liquid in the two vertical tubes is $h$. The incorrect statement is