The velocity of kerosene in a horizontal pipe is $5 \ m/s$. What is the velocity head in $m$? (Take $g = 10 \ m/s^2$)

Water from a tap emerges vertically downwards with an initial speed of $1.0\,ms^{-1}.$ The cross-sectional area of the tap is $10^{-4}\,m^2.$ Assume that the pressure is constant throughout the stream of water and that flow is streamlined. The cross-sectional area of the stream,$0.15\,m$ below the tap would be: (take $g = 10\,ms^{-2}$ )

$A$ tank of height $15 \ m$ and cross-section area $10 \ m^2$ is filled with water. There is a small hole of cross-section area $a$ which is much smaller than the container, located at a height of $12 \ m$ from the base of the container. How much force should be applied with a piston at the top level, so that the water coming out of the hole hits the ground at a distance of $16 \ m$ (in $kN$)? (Take, density of water $\rho = 1000 \ kg \ m^{-3}$ and $g = 10 \ m/s^2$)

$A$ 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 . . . . . . $\times 10^{-3}\,m^{3}\,s^{-1}$.

Water flows in a horizontal tube (see figure). The pressure of water changes by $700 \; Nm^{-2}$ between $A$ and $B$ where the area of cross-section are $40 \; cm^{2}$ and $20 \; cm^{2},$ respectively. Find the rate of flow of water through the tube in $cm^{3} / s$. (Density of water $= 1000 \; kgm^{-3}$)

$A$ manometer connected to a closed tap reads $3.5 \times 10^5 \ N/m^2$. When the valve is opened,the reading of the manometer falls to $3.0 \times 10^5 \ N/m^2$. The velocity of the flow of water is ........ $m/s$.