Two pipes of radii $2 \, cm$ and $4 \, cm$ are connected in series. What is the ratio of the flow velocities of the fluid in these pipes?

Water is flowing through two horizontal pipes of different diameters which are connected together. The diameters of the two pipes are $3\, cm$ and $6\, cm$ respectively. If the speed of water in the narrower pipe is $4\, m/s$ and the pressure is $2.0 \times 10^4\, Pa$,then the speed of water in the wider pipe is ........ $m/s$.

An engine pumps a liquid of density $d$ continuously through a pipe of cross-sectional area $A$. If the speed of the liquid passing through the pipe is $V$,what is the kinetic energy per unit time imparted to the liquid?

Two water pipes of diameter $2 \,cm$ and $4 \,cm$ are separately connected to a main supply line. The velocity of flow of water in the pipe of $2 \,cm$ diameter is

$A$ horizontal tube of non-uniform cross-section has radii of $0.1\,m$ and $0.05\,m$ respectively at $M$ and $N$. For a streamline flow of liquid, the rate of liquid flow is:

Water coming out of the mouth of a tap and falling vertically in streamline flow forms a tapering column,i.e.,the area of cross-section of the liquid column decreases as it moves down. Which of the following is the most accurate explanation for this?