Embibe Experts Solutions for Chapter: Viscosity and Surface Tension, Exercise 4: Exercise - 4

Eight raindrops of radius one $\mathrm{mm}$ each falling down with a terminal velocity of $5 \mathrm{cm} {\mathrm{s}}^{–1}$ coalesces to form a bigger drop. Calculate the terminal velocity of the bigger drop.

A long cylinder of the radius $R_1$ is displaced along its axis with a constant velocity $v_0$, inside a stationary co-axial cylinder of radius $R_2$. The space between the cylinders is filled with viscous liquid. Find the velocity of the liquid as a function of the distance $r$ from the axis of the cylinders. The flow is laminar.