Water is flowing through a channel (lying in a vertical plane) as shown in the figure. Three sections $A, B$ and $C$ are shown. Sections $B$ and $C$ have equal area of cross section. If $P_A, P_B$ and $P_C$ are the pressures at $A, B$ and $C$ respectively then

Alaminar stream is flowing vertically down from a tap of cross-section area $1$ $cm^2$. At a distance $10 $ $cm$ below the tap, the cross-section area of the stream has reduced to $1/2$ $cm^2$. The volumetric flow rate of water from the tap must be about ........ $litre/\min$

In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the upper and lower surfaces of the wing are $70 \;m s ^{-1}$ and $63\; m s ^{-1}$ respectively. What is the lift on the wing if its area is $2.5 \;m ^{2}$ ? Take the density of atr to be $1.3\; kg m ^{-3} .$

The platelets are drifting with the blood flowing in a streamline flow through a horizontal artery as shown below Artery is contracted in region $II$. Choose the correct statement.

The weight of an aeroplane flying in the air is balanced by

Why does an airplane run a certain length on the runway first before taking off ?