The Physics Of Superheros

Can He Swing From A Thread?- Centripetal Acceleration

In this chapter of "The Physics Of Superheros" Kakalios talks about Spider-man and if he would actually be able to swing from one building to another using only his webs. He starts off by asking the question: Would it actually be possible for Spider-man to swing from building to building?

He starts looking for the answer in Newtons second law of motion, F=MA, which states that force is needed to change an object's motion, and that if no force acts upon an object then it will persist in uniform motion. He then talks about the ability to change the direction of motion in that an external force is needed and when producing an external force an acceleration is produced in the direction that it acts. Kakalios then continues to talk about vertical velocity and the forces acting upon him as he is falling. He transitions to talking about the way Spider-man swings from building to building, and how his trajectory is a semicircle instead of a straight line. So while his magnitude of speed does not change his direction of motion is constantly changing. This force, of course, comes from the tension in the webbing, and therefore has to do double duty and supply two forces, one for Spider-man and the other to divert him in a circular motion.

He then goes on to talk about Spider-mans' spider web that he uses. He says that if that web is the same constitution as spider silk that it's completely plausible for the webbing to hold him up. In conclusion, besides the whole getting bit by a spider and suddenly having super powers, Spider-man could theoretically exist.