True or False: A discontinuity may not affect the usefulness of a part.

The statement "A discontinuity may not affect the usefulness of a part" is indeed true because not all discontinuities necessarily compromise the functionality or performance of a given component. Discontinuities can manifest as flaws, defects, or irregularities within a material, such as cracks, voids, or inclusions. However, their impact on a part's usefulness heavily depends on various factors, including the material type, the location and size of the discontinuity, the specific application of the part, and the expected loading conditions during service.

For instance, a small surface imperfection on a cosmetic part may not hinder its performance or aesthetic value. Likewise, certain materials exhibit different tolerances for imperfections; for example, some composites can still perform effectively even if they contain minor voids, as their overall structural integrity might remain intact. Therefore, a discontinuity's relevance to a part's functionality can vary significantly based on these factors.

Regarding the other options, not all materials behave the same way, so stating that it is always true for all materials is not accurate. Similarly, asserting that this notion is only applicable to non-metallic parts disregards the complexities of materials science across both metallic and non-metallic domains. Thus, the statement stands as true, emphasizing