Question:medium
A rain drop of diameter 1 mm falls with a terminal velocity of 0.7 ms$^{-1}$ in air. If the coefficient of viscosity of air is $2\times10^{-5}$ Pas, the viscous force on the rain drop is
A rain drop of diameter 1 mm falls with a terminal velocity of 0.7 ms$^{-1}$ in air. If the coefficient of viscosity of air is $2\times10^{-5}$ Pas, the viscous force on the rain drop is
Show Hint
Stokes' Law, $F_v = 6\pi\eta r v$, describes the drag force on a sphere moving slowly through a viscous fluid. Remember that at terminal velocity, this viscous drag force exactly balances the net downward force (gravity minus buoyancy).
Updated On: Mar 30, 2026
- $13.2\times10^{-8}$ N
- $6.6\times10^{-8}$ N
- $26.4\times10^{-8}$ N
- $10.4\times10^{-8}$ N
Show Solution
The Correct Option is A
Solution and Explanation
Was this answer helpful?
0
Top Questions on Mechanical Properties of Fluids
- An ideal fluid is flowing in a non-uniform cross-sectional tube XY (as shown in the figure) from end X to end Y. If $K_1$ and $K_2$ are the kinetic energy per unit volume of the fluid at X and Y respectively, then the correct option is :
- NEET (UG) - 2024
- Physics
- Mechanical Properties of Fluids
- If \(W_1\) is the work done in increasing the radius of a soap bubble from 'r' to '2r' and \(W_2\) is the work done in increasing the radius of the soap bubble from '2r' to '3r', then \(W_1: W_2 =\)
- TS EAMCET - 2025
- Physics
- Mechanical Properties of Fluids
- The maximum length of water column that can stay without falling in a vertically held capillary tube of diameter 1mm and open at both the ends is (Acceleration due to gravity = 10 ms$^{-2}$ and surface tension of water = 0.07 Nm$^{-1}$)
- TS EAMCET - 2025
- Physics
- Mechanical Properties of Fluids
- A body is allowed to fall freely under gravity from a height of 15 m from the ground. At a point in its path, if the kinetic energy of the body is 200% more than its potential energy, then the velocity of the body at that point is (Acceleration due to gravity = 10 $ms^{-2}$)
- TS EAMCET - 2025
- Physics
- Mechanical Properties of Fluids
- Want to practice more? Try solving extra ecology questions todayView All Questions