Water is flowing through a horizontal pipe of non-uniform cross-section. In the region of the narrowest part inside the pipe,the water will have

Water is flowing through a horizontal pipe of non-uniform cross-section. At the extreme narrow portion of the pipe, the water will have

Water from a tap emerges vertically downwards with an initial velocity of $4 \,m/s$. The cross-sectional area of the tap is $A$. The flow is steady and the pressure is constant throughout the stream of water. The distance $h$ vertically below the tap,where the cross-sectional area of the stream becomes $\frac{2}{3} A$,is (take $g = 10 \,m/s^2$): (in $\,m$)

$A$ 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 $g = 10 \ m/s^2$)

In a test experiment on a model aeroplane in a wind tunnel,the flow speeds on the upper and lower surfaces of the wings are $70 \,m/s$ and $65 \,m/s$ respectively. If the wing area is $2 \,m^2$,the lift of the wing is . . . . . . $N$. (Given density of air $= 1.2 \,kg/m^3$)

The pans of a physical balance are in equilibrium. Air is blown under the right hand pan; then the right hand pan will