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

The figure below shows a liquid being pushed out of a tube by a piston having a cross-sectional area of $2.0\,cm^2$. The cross-sectional area at the outlet is $10\,mm^2$. If the piston is pushed at a speed of $4\,cm/s$,the speed of the outgoing fluid is $.........\,cm/s$.

Fountains usually seen in gardens are generated by a wide pipe with an enclosure at one end having many small holes. Consider one such fountain which is produced by a pipe of internal diameter $2 \ cm$ in which water flows at a rate $3 \ ms^{-1}$. The enclosure has $100$ holes each of diameter $0.05 \ cm$. The velocity of water coming out of the holes is (in $ms^{-1}$):

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?

An ideal fluid flows through a pipe of circular cross-section with diameters $5 \ cm$ and $10 \ cm$ as shown. The ratio of velocities of the fluid at $A$ and $B$ is

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