Vikas TU
Last Activity: 4 Years ago
The force which causes the rope to return is an elastic force. Just as with a spring it tries to return to it's original shape because it has been deformed.
Yes, it is generally discussed in term of tension in the rope, but what is tension if not the elastic forces between the molecules of the fibers. Keep in mind that all materials stretch a little under tension. It's not much in a natural fiber rope, but it is some---ask anyone who has ever tried to walk a taunt-line.
It is also worth being aware that
Diagrams in texts generally use a very exaggerated transverse scale.
The claim of purely transverse motion depends on small displacements
Demos where a real rope is driven by a wheel, do introduce some longitudinal motion
