$1$ poiseille $=$ .......... poise

The terminal velocity of a copper ball of radius $5\,mm$ falling through a tank of oil at room temperature is $10\,cm\,s ^{-1}$. If the viscosity of oil at room temperature is $0.9\,kg\,m ^{-1} s ^{-1}$, the viscous drag force is :

A spherical body of radius $R$ consists of a fluid of constant density and is in equilibrium under its own gravity. If $P ( r )$ is the pressure at $r ( r < R )$, then the correct option$(s)$ is(are)

$(A)$ $P ( I =0)=0$ $(B)$ $\frac{ P ( r =3 R / 4)}{ P ( r =2 R / 3)}=\frac{63}{80}$

$(C)$ $\frac{ P ( r =3 R / 5)}{ P ( r =2 R / 5)}=\frac{16}{21}$ $(D)$ $\frac{ P ( r = R / 2)}{ P ( r = R / 3)}=\frac{20}{27}$

Write $\mathrm{SI}$ and $\mathrm{CGS}$ unit of coefficient of viscosity.

The velocity of a small ball of mass $\mathrm{M}$ and density $d,$ when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is $\frac{\mathrm{d}}{2}$, then the viscous force acting on the ball will be :

The displacement of a ball falling from rest in a viscous medium is platted against time. Choose a possible option