Explanation:

Pascal second (Pa·s) is the unit of dynamic viscosity. Dynamic viscosity is a measure of a fluid's resistance to flow under an applied force or stress. It characterizes the internal friction of a moving fluid and is related to the fluid's resistance to shear or deformation.

Dynamic Viscosity:
Dynamic viscosity, also known as absolute viscosity, is a property of fluids that determines the internal frictional resistance to flow. It is a measure of the fluid's ability to resist shear stress or deformation when subjected to an applied force. The higher the dynamic viscosity, the greater the resistance to flow.

Units of Viscosity:
Viscosity can be expressed in various units depending on the system of measurement being used. In the International System of Units (SI), dynamic viscosity is typically measured in pascal seconds (Pa·s). The pascal second is equivalent to one newton-second per square meter (N·s/m²).

Other Units of Viscosity:
In addition to pascal seconds, there are other commonly used units of dynamic viscosity:

- Poise (P): The poise is a non-SI unit of dynamic viscosity, equal to 0.1 pascal second (Pa·s). It is named after Jean Louis Marie Poiseuille, a French physicist and physician who made significant contributions to the understanding of fluid dynamics.
- Centipoise (cP): The centipoise is a subunit of the poise and is equal to one hundredth (1/100) of a poise. It is commonly used to express the viscosity of liquids, especially in industries such as petroleum and pharmaceuticals.

Conclusion:
In summary, Pascal second (Pa·s) is the unit of dynamic viscosity. It is a measure of a fluid's resistance to flow under an applied force or stress. Other commonly used units of dynamic viscosity include the poise (P) and centipoise (cP).