Math Question that a have being thinking about.

Question

If a cord holds a fixed weight, how much weight would two cord put together hold; and if it were to be braided, how much more would the braided cord would be able to carried above the two unbraided one?

Answer 1

Hi Jonathan,

 

Your intuition is probably correct about two cords.  If one cord snaps when force F is applied, then pulling on two cords with equally distributed force 2F applies force F on each cord.  Thus, the cords would both snap at the same time, when force 2F is applied. If you don't equally apply the force, however, then the tighter cord will snap first, followed immediately by the other cord.

 

You can't do any better than that in theory.  However, if you braid rope, you minimize undesirable properties like kinkage or uneven strain.  Thus, braiding produces a stronger rope in practice.  The advantage depends on a number of factors, such as whether the rope is twisting, the friction between fibers, and the amount the rope stretches.

 

You can read quite a bit more about this topic here:

 

http://www.animatedknots.com/rope.php?Categ=splicing

 

I hope this helps.

 

Regards,

Mike N.