Question

What is the separation of between two ends of a thread

Answer 1

Hope I got your question right,here's the answer:

Displacement, the perpendicular distance between the two ends of the thread.
Note:It need not to be the length of the thread always.For example, if the thread is completely stretched in any particular direction,then the length of the thread is the displacement of its two ends,otherwise the displacement of the two ends is the shortest distance between the ends which can be less than the length of the thread.

Hope this helps!