Water falls from a tap,down the streamline. What happens to the cross-sectional area of the water stream?

The blades of a windmill sweep out a circle of area $A$. If the wind flows at a velocity $v$ perpendicular to the circle,then the mass of the air of density $\rho$ passing through it in time $t$ is

An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipe are $6.4 \; cm$ and $4.8 \; cm,$ respectively. The ratio of the minimum and the maximum velocities of the fluid in this pipe is:

$A$ water spray gun is attached to a hose of cross-sectional area $30 \text{ cm}^2$. The gun comprises $10$ perforations, each of cross-sectional area $15 \text{ mm}^2$. If the water flows in the hose with a speed of $50 \text{ cm/s}$, calculate the speed at which the water flows out from each perforation. (Neglect any edge effects)

$A$ pipe having an internal diameter $D$ is connected to another pipe of the same size. Water flows into the second pipe through $n$ holes,each of diameter $d$. If the water in the first pipe has speed $v$,the speed of water leaving the second pipe is

The total area of cross-section is $0.25\,m^2$. If the blood is flowing at the rate of $100\,cm^3/s$,then the average velocity of flow of blood through the capillaries is ........ $mm/s$.