The working of an atomizer depends upon:

$A$ liquid of density $750\,kg\,m^{-3}$ flows smoothly through a horizontal pipe that tapers in cross-sectional area from $A_{1} = 1.2 \times 10^{-2}\,m^{2}$ to $A_{2} = \frac{A_{1}}{2}$. The pressure difference between the wide and narrow sections of the pipe is $4500\,Pa$. The rate of flow of liquid is . . . . . . $\times 10^{-3}\,m^{3}\,s^{-1}$.

What is the nature of the pressure-distance graph for the pipe shown in the figure?

Water is flowing through a horizontal tube having cross-sectional areas of its two ends as $A$ and $A'$ such that the ratio $A/A'$ is $5$. If the pressure difference of water between the two ends is $3 \times 10^5 \, N \, m^{-2}$,the velocity of water with which it enters the tube will be ......... $m \, s^{-1}$ (neglect gravity effects).

$A$ plane is in level flight at constant speed and each of its two wings has an area of $40 \,m^2$. If the speed of the air is $180 \,km/h$ over the lower wing surface and $252 \,km/h$ over the upper wing surface,the mass of the plane is . . . . . . $kg$. (Take air density to be $1 \,kg \,m^{-3}$ and $g=10 \,ms^{-2}$)

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