Water flows through the tube shown. The cross-sectional areas of the wide and narrow parts are $5 \text{ cm}^2$ and $2 \text{ cm}^2$,respectively. The rate of flow is $500 \text{ cm}^3/\text{s}$. Find the difference in the mercury level of the $U$-tube in $\text{cm}$.

Air streams horizontally past an airplane. The speed over the top surface is $60 \, m/s$ and that under the bottom surface is $45 \, m/s$. The density of air is $1.293 \, kg/m^3$. The difference in pressure is ....... $N/m^2$.

Bernoulli's principle is based on the law of conservation of

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 ....... $Pascal$.

The diagram shows a venturimeter through which water is flowing. The speed of water at $X$ is $2 \, cm/s$. The speed of water at $Y$ (taking $g = 1000 \, cm/s^2$) is ........ $cm/s$.

Explain the upward force (dynamic lift) acting on an airplane wing.