In a test experiment on a model aeroplane in a wind tunnel,the flow speeds on the upper and lower surfaces of the wings are $70 \,m/s$ and $65 \,m/s$ respectively. If the wing area is $2 \,m^2$,the lift of the wing is . . . . . . $N$. (Given density of air $= 1.2 \,kg/m^3$)

Obtain Bernoulli's equation for a fluid at rest.

$A$ 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

In the diagram shown,the difference in the height of the liquid columns in the two tubes of the manometer is $5\, cm$. The cross-sectional areas of the tube at $A$ and $B$ are $6\, mm^2$ and $10\, mm^2$ respectively. The rate at which water flows through the tube is ........ $cc/s$ $(g = 10\, m/s^2)$.

Figures $(a)$ and $(b)$ refer to the steady flow of a non-viscous liquid. Which of the two figures is incorrect? Why?

Water (of density $\varrho$) flows steadily through a horizontal pipe of variable cross-section. If the pressure of water is $P$ at a point where the flow speed is $V$,then the pressure at another point where the flow speed becomes $3V$ is: