If the terminal speed of a sphere of gold (density $19.5 \,kg / m ^2$ ) is $0.2 \,m / s$ in a viscous liquid (density $=1.5 \,kg / m ^3$ ), find the terminal speed of a sphere of silver (density $=10.5 \,kg / m ^3$ ) of the same size in the same liquid is ............ $m / s$

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 ........ $N/m^2$

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

A spherical solid ball of volume $V$ is made of a material of density $\rho_1$. It is falling through a liquid of density $\rho_1 (\rho_2 < \rho_1)$. Assume that the liquid applies a viscous force on the ball that is proportional to the square of its speed $v$, i.e., $F_{viscous} = -kv^2 (k > 0)$. The terminal speed of the ball is

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 ........ $m$

A cubical block of side $‘a’$ and density ‘$\rho $’ slides over a fixed inclined plane with constant velocity $‘v’$. There is a thin film of viscous fluid of thickness $‘t’$ between the plane and the block. Then the coefficient of viscosity of the thin film will be