Physics - Fluid Question with Solution | TestHub

Weight of the body $\mathrm{W}=\mathrm{mg}=\frac{4}{3}\pi {\mathrm{r}}^3\rho \mathrm{g}$ $\mathrm{T}=\frac{4}{3}\pi {\mathrm{r}}^3\sigma \mathrm{g}$ and $\mathrm{F}=6\pi \eta \mathrm{vr}$ When the body attains terminal velocity net force acting on the body is zero. i.e., $\mathrm{W}-\mathrm{T}-\mathrm{F}=0$ And terminal velocity $\mathrm{v}=\frac{2}{9}\frac{{\mathrm{r}}^2(\rho -\sigma )\mathrm{g}}{\eta }$ As in case of upward motion upward force is twice its effective weight, therefore, it will move with same speed $10\mathrm{cm}/\mathrm{s}$