A boat carrying a number of large stones is floating in a water tank. What would happen to the water level if a few stones are unloaded into water

A sphere of mass $M$ and radius $R$ is falling in a viscous fluid. The terminal velocity attained by the falling object will be proportional to

Water is flowing through two horizontal pipes of different diameters which are connected together. The diameters of the two pipes are $3\, cm$ and $6\, cm$ respectively. If the speed of water in narrower pipe is $4\, m/sec$ and the pressure is $2.0\times10^4$ pascal, then the speed of water in the wider pipe is ........ $m/sec$

Two equal drops are falling through air with a steady velocity of $5\, cm/second$. If two drops coalesce to form one drop then new terminal velocity will be

A square hole of side length $l$ is made at a depth of $h$ and a circular hole of radius $r$ is made at a depth of $4\,h$ from the surface of water in a water tank kept on a horizontal surface. If $l << h,\,r << h$ and the rate of water flow from the holes is the same, then $r$ is equal to

A space $2.5\ cm$ wide between two large plane surfaces is filled with oil. Force required to drag a very thin plate of area $0.5\ m^2$ just midway the surfaces at a speed of $0.5\ m/sec$ is $1\ N$. The coefficient of viscosity in $kg-s/m^2$ is