Viscous force and shear stress in flow between parallel plates

[jordansas]

Hi all,

Im having a bit of trouble understanding the concept of viscosity in the scenario of a fluid between two plates, with one moving and one being stationary: what is the relevance between the viscous force of the fluid and the shear stress on the fluid given by mu(du/dy) ?

 

[Chestermiller]

The viscous force is equal to the shear stress times the area over which the shear stress is acting.