Q 11-09-062JEE MainJEE Main 2024 (6 Apr, Shift 1)Easy
A small ball of mass $m$ and density $\rho$ is dropped in a viscous liquid of density $\rho_0$. After some time, the ball falls with a constant velocity. The viscous force on the ball is
Answer: (D) $mg\left(1 - \dfrac{\rho_0}{\rho}\right)$
At terminal velocity the net force is zero: $F_v = mg - F_B$.
Buoyant force: $F_B = V\rho_0g = \dfrac{m}{\rho}\rho_0g$.
$$F_v = mg\left(1 - \frac{\rho_0}{\rho}\right)$$
Solution by Sreeraj P, M.Sc Physics