A .......... $m/s$ speed the velocity head of water is equal to pressure head of $40\, cm$ of $Hg$ .

A hollow sphere of radius $R$ is filled completely with an ideal liquid of density $\rho $ . sphere is moving horizontally with an acceleration $2\ g$ , where $g$ is acceleration due to gravity in the space. If minimum pressure of liquid is $P_0$ , then pressure at the centre of sphere is 

Water falls from a tap, down the streamline

Horizontal tube of non-uniform cross-section has radius of  $0.2\,m$ and  $0.1\,m$  respectively at $P$  and  $Q$ . For streamline flow of liquid, the rate of liquid flow

A wooden cube first floats inside water when a $200\,g$ mass is placed on it. When the mass is removed the cube is $2\,cm$ above water level. The side of cube is ......... $cm$

The area of cross section of the wides tube shown in the figure is $800\,cm^2$. If a mass of $12\,kg$ is placed on the massless piston, the difference in the heights $h$ in the level of water in two tubes ........ $m$