At what speed, the velocity head of water is equal to pressure head of $40 \,cm$ of mercury is ........ $m / s$

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

A liquid flows through a horizontal tube. The velocities of the liquid in the two sections which have areas of cross-section $A_1$ and $A_2$ are $v_1$ and $v_2$ respectively. The difference in the levels of the liquid in the two vertical tubes is $h$ . The incorrect statement is

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 $1.3\; kg m ^{-3} .$

A body of density $\rho$ is dropped from rest from a height $h$ into a lake of density $\sigma$, where $\sigma > \rho$. Neglecting all dissipative forces, the maximum depth to which the body sinks before returning to float on surface ..........

Obtain Bernoulli’s equation of rest fluid.