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 ........ $cm/s$.

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 ....... $Pascal$.

Does it matter if one uses gauge instead of absolute pressures in applying Bernoulli's equation? Explain.

Water is flowing through a horizontal tube as shown in the figure. Its diameters at two points are $0.3\,m$ and $0.1\,m$ respectively. The pressure difference between these two points is equal to $0.8\,m$ of water column. Find the rate of flow of water in the tube in $ltr/s$.

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 ....... $N/m^2$.

Water is moving with a speed of $5.0\,m/s$ through a pipe of cross-sectional area $4.0\,cm^2$. The water gradually descends $10\,m$ as the pipe increases in area to $8.0\,cm^2$. If the pressure at the upper level is $1.5 \times 10^5\,Pa$,the pressure at the lower level will be: