Which term refers to the slow, permanent deformation of a solid material under the influence of a mechanical stress?

• A. Density
• B. Creep
• C. Creosote
• D. Cupping

Answer: (B)

Creep is the slow, permanent deformation of a solid under a constant mechanical stress. When a material experiences a sustained load, it gradually changes shape or length over time, and that change remains even if the load stays the same. This time-dependent, irreversible behavior arises from atomic-scale processes like diffusion and dislocation movement that let the material rearrange under stress, especially at higher temperatures. The other terms don’t describe this phenomenon: density is just mass per volume, creosote is a wood-preserving chemical, and cupping refers to a surface distortion often due to moisture or suction rather than time-dependent deformation under load.