Air is streaming past a horizontal aeroplane wing such that its speed is $120\, m/s$ over the upper surface and $90\, m/s$ at the lower surface. If the density of air is $1.3\, kg/m^3$ and the wing is $10\, m$ long and has an average width of $2\, m$ , then the difference of the pressure on the two sides of the wing is ........ $N/m^2$

Two liquids having densities $d_1$ and $d_2$ are mixed in such a way that both have same mass. The density of the mixture is ............

The height of water in a tank is $H$. The range of the liquid emerging out form a hole in the wall of the tank at a depth $\frac{{3H}}{4}$ from the upper surface of water, will be

The diagram (figure) shows a venturimeter, through which water is flowing. The speed of water at $X$ is $2\,cm/s$. The speed of water at $Y$ (taking $g = 1000\,cm/s^2$ ) is ........ $cm/s$

A cubical block is floating in a liquid with half of its volume immersed in the liquid. When the whole system accelerates upwards with a net acceleration of $g/3$ The fraction of volume immersed in the liquid will be

A boat carrying a number of stones is floating in a water tank. If the stones are unloaded into water, the water level in the tank will ............