A substance that deforms continuously under shear stress is best described as a:

A substance that deforms continuously under shear stress is best described as a:

• A. Fluid
• B. Solid
• C. Gas
• D. Plasma

Answer: (A)

A substance that deforms continuously under shear stress is a fluid because fluids keep flowing when a shear force is applied. They don’t maintain a fixed shape; instead, they continually rearrange and shear, resulting in ongoing deformation and flow. Solids, by contrast, resist continuous deformation and only deform up to a yield point or elastic limit. Gases and plasmas are also fluids in the broad sense, but the description matches the general behavior of fluids most directly.

A substance that deforms continuously under shear stress is a fluid because fluids keep flowing when a shear force is applied. They don’t maintain a fixed shape; instead, they continually rearrange and shear, resulting in ongoing deformation and flow. Solids, by contrast, resist continuous deformation and only deform up to a yield point or elastic limit. Gases and plasmas are also fluids in the broad sense, but the description matches the general behavior of fluids most directly.