Question

The normal stress is the same in all directions at a point in a fluid only when

• A. The fluid is frictional
• B. The fluid is frictionless and incompressible
• C. The fluid has zero viscosity and is at rest
• D. One fluid layer has no motion relative to an adjacent layer

Answer 1

Answer:

D. One fluid layer has no motion relative to an adjacent layer

The normal stress is the same in all directions at a point in a fluid when adjacent fluid layers are not moving relative to each other. This condition is known as fluid equilibrium. Pascal's principle states that pressure applied to fluids is equally transmitted in all directions, to all parts of the fluid and to all parts of a container. This principle applies when the enclosed liquid is in equilibrium of rest.