Final answer:
Fluids cannot withstand shear stress and will flow when subjected to such forces, demonstrating zero shear strength, particularly in a scenario where fluid is sandwiched between two plates with one plate moving.
Step-by-step explanation:
The question relates to the behavior of a fluid under stress between two plates. According to the provided figures and summary from a physics perspective, when two parallel plates have fluid between them, and the bottom plate is held fixed while the top plate is moved, the fluid exhibits a continuous variation in speed from the velocity of the top plate to zero at the bottom plate where it is at rest.
This occurs because fluids have zero shear strength, meaning they cannot resist the shearing force and will flow or deform continuously under such a force. The motion described is a type of laminar flow, where the fluid layers move parallel and do not mix, and it's a fundamental concept in studying fluid viscosity.
False. A fluid with a density of 1400 will not necessarily have a nonzero stress on a bottom plate. The stress on a bottom plate depends on the pressure exerted by the fluid and the area of the plate. If the fluid is not exerting any pressure on the plate, then the stress would be zero.