Let’s Do the Shocking Physics of Why Power Lines Sag by Rhett Allain from on 2017-04-27 12:00 (#2MJGG) When a cable is supported by the two ends, it will hang down a bit depending on the tension in the cable. How can you model this cable sag with a computer? The post Let's Do the Shocking Physics of Why Power Lines Sag appeared first on WIRED.