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

Water flows through a horizontal pipe of varying cross-section at a rate of $0.314 \,m^3 \,s^{-1}$. The velocity of water at a point where the radius of the pipe is $10 \,cm$ is (in $\,m/s$)

Why does fluid flow faster in a narrow tube?

The surface of water in a water tank of cross-sectional area $750 \,cm^2$ on the top of a house is '$h$' $m$ above the tap level. The speed of water coming out through the tap of cross-sectional area $500 \,mm^2$ is $30 \,cm/s$. At that instant, $\frac{dh}{dt}$ is $x \times 10^{-3} \,m/s$. The value of '$x$' will be:

Water flows through a horizontal pipe at a speed $V$. The internal diameter of the pipe is $d$. If the water is emerging from a nozzle at a speed $V_{1}$,then the diameter of the nozzle is

In a streamlined flow,the velocity of a fluid at a given point