“…[4]) to be the one for which the stretch is constrained to be equal to 1, whatever system of forces is applied to it. As in [23], some authors refer to it as a chain which is a long but very thin material that is inextensible but completely flexible, and hence mathematically described as a rectifiable curve of fixed length. Dynamics of pipes, flagella, chains, or ribbons of rhythmic gymnastics, mechanism of whips, and galactic motion are only a few phenomena and applications that can be related to inextensible strings (see [6,14,12] for more details).…”