alkupituus

Alkupituus is a Finnish term that translates roughly to initial length or original length. It is used in Finnish-language technical and scientific writing to denote the length of an object or segment at the start of a process, measurement, or transformation. The word is formed from alkua (beginning, initial) and pituus (length).

In physics and engineering, alkupituus often serves as the reference length in problems involving deformation, stretching, or compression. A common usage is to define L0 as alkupituus and describe subsequent changes with L(t) = alkupituus + ΔL(t). This convention helps distinguish the starting size from later measurements and changes.

In materials science, polymer physics, and related fields, alkupituus can refer to the original length of a specimen, fiber, or molecular chain before loading, processing, or thermal treatment. It provides a baseline for calculating strain, elongation, or shrinkage.

Linguistically, alkupituus is primarily a technical term in Finnish. In English-language translations within Finnish sources, it is often rendered as initial length or original length, depending on context. The concept ties to the broader Finnish term pituus (length) and to alkusääntöjä (starting conventions) in mathematical and engineering contexts.

See also: pituus, alku, initial value.