The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is \(\frac{d}{2}\), then the viscous force acting on the ball will be
2Mg
\(\frac{Mg}{2}\)
Mg
\(\frac{3}{2}Mg\)
The Correct Option is B
Solution and Explanation
Top Questions on mechanical properties of fluid
- A fluid of density \( 800 \, \text{kg/m}^3 \) is flowing through a pipe of varying cross-sectional area. The velocity of the fluid at point A is \( 2 \, \text{m/s} \), and the velocity at point B is \( 4 \, \text{m/s} \). If the cross-sectional area at point A is \( 1 \, \text{m}^2 \), find the cross-sectional area at point B.
- MHT CET - 2025
- Physics
- mechanical properties of fluid
- A pipe has a radius of 2 cm at one end and 1 cm at the other end. The velocity of the water at the wider end is 5 m/s. What is the velocity of the water at the narrower end, assuming incompressible flow?
- MHT CET - 2025
- Physics
- mechanical properties of fluid
- A cylindrical pipe has a radius of \( 0.1 \, \text{m} \). If the speed of water flowing through the pipe is \( 2 \, \text{m/s} \), calculate the volume flow rate of water through the pipe.
- MHT CET - 2025
- Physics
- mechanical properties of fluid
- The magnifying power of a telescope is \( 9 \). When adjusted for parallel rays, the distance between the objective and eyepiece is 20 cm. The ratio of the focal length of the objective lens to the focal length of the eyepiece is:
- BITSAT - 2024
- Physics
- mechanical properties of fluid
- A hole of area 1 mm\(^2\) opens in the pipe near the lower end of a large water storage tank, and a stream of water shoots from it. If the top of the water in the tank is 20 m above the point of the leak, the amount of water escapes in 1 s is:
- OJEE - 2024
- Physics
- mechanical properties of fluid
Questions Asked in NEET exam
- Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is :
- NEET (UG) - 2024
- work, energy and power
The following graph represents the T-V curves of an ideal gas ( where T is the temperature and V the volume) at three pressures P1, P2 and P3 compared with those of Charles's law represented as dotted lines.
Then the correct relation is :- NEET (UG) - 2024
- Ideal Gases
- In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100x (kcal m-2)yr-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?
- NEET (UG) - 2024
- Ecosystems
- 1 gram of sodium hydroxide was treated with 25 ml. of 0.75 M HCI solution, the mass of sodium hydroxide left unreacted is equal to
- NEET (UG) - 2024
- Structural Representations Of Organic Compounds
In the given figure, which component has thin outer walls and highly thickened inner walls?
- NEET (UG) - 2024
- Cell Wall
Concepts Used:
Viscosity
Viscosity is a measure of a fluid’s resistance to flow. The SI unit of viscosity is poiseiulle (PI). Its other units are newton-second per square metre (N s m-2) or pascal-second (Pa s.) The dimensional formula of viscosity is [ML-1T-1].
Viscosity: Formula
Viscosity is measured in terms of a ratio of shearing stress to the velocity gradient in a fluid. If a sphere is dropped into a fluid, the viscosity can be determined using the following formula:
η = [2ga2(Δρ)] / 9v
Where ∆ρ is the density difference between fluid and sphere tested, a is the radius of the sphere, g is the acceleration due to gravity and v is the velocity of the sphere.
Viscosity: Types
- Dynamic viscosity: When the viscosity is measured directly by measuring force. It is defined as the ratio of shear stress to the shear strain of the motion. Dynamic viscosity is used to calculate the rate of flow in liquid.
- Kinematic viscosity: There is no force involved. It can be referred to as the ratio between the dynamic viscosity and density of the fluid. It can be computed by dividing the dynamic viscosity of the fluid with fluid mass density.
- Laminar flow: Laminar flow is the type of flow in which the fluid moves smoothly or in a regular path from one layer to the next. Laminar flow occurs in lower velocities.