Viscous drag refers to the resistance experienced by an object moving through a fluid due to the fluid's viscosity, which is a measure of its internal friction. This drag force increases with the speed of the object and is influenced by the fluid's properties and the object's shape. Stokes' Law provides a mathematical description of viscous drag for small spherical objects moving slowly through a viscous fluid, stating that the drag force F is proportional to the object's radius r, the fluid's viscosity η, and the object's velocity v. The law is expressed as F=6πηrv, indicating that larger objects or those moving faster will experience greater drag. Stokes' Law is particularly applicable in laminar flow conditions, where the fluid moves in parallel layers with minimal turbulence.
What is viscous drag?
Viscous drag is the resistance force experienced by an object moving through a fluid, caused by the fluid's viscosity, which is a measure of its internal friction.
How does the speed of an object affect viscous drag?
The viscous drag force increases with the speed of the object; as the object moves faster through the fluid, the resistance it encounters also increases.
What is Stokes' Law?
Stokes' Law describes the viscous drag force acting on a small spherical object moving slowly through a viscous fluid, expressed as F=6πηrv, where F is the drag force, η is the fluid's viscosity, r is the radius of the sphere, and v is its velocity.
In what type of flow is Stokes' Law applicable?
Stokes' Law is applicable in laminar flow conditions, where the fluid moves in smooth, parallel layers with minimal turbulence.
What factors influence the viscous drag force on an object?
The factors influencing viscous drag include the object's shape, size (radius), the fluid's viscosity, and the object's velocity relative to the fluid.
What does Stokes' Law describe?
a) The relationship between pressure and velocity in a fluid
b) The drag force on a spherical object moving through a viscous fluid
c) The buoyant force acting on submerged objects
d) The conservation of mass in fluid dynamics
Answer: b) The drag force on a spherical object moving through a viscous fluid
In Stokes' Law, the drag force F is proportional to which of the following?
a) The square of the velocity
b) The radius of the sphere
c) The density of the fluid
d) The temperature of the fluid
Answer: b) The radius of the sphere
Which of the following conditions is necessary for Stokes' Law to be applicable?
a) High Reynolds number
b) Turbulent flow
c) Laminar flow
d) Compressible flow
Answer: c) Laminar flow
What happens to the viscous drag force as the speed of an object increases?
a) It decreases
b) It remains constant
c) It increases
d) It becomes negligible
Answer: c) It increases
Which of the following factors does NOT affect the viscous drag force on a sphere?
a) The radius of the sphere
b) The viscosity of the fluid
c) The shape of the sphere
d) The velocity of the sphere
Answer: c) The shape of the sphere