But in this case, the arms didn’t get “pulled off”, they were severed by the whipping of the broken rope. Other people have lost fingers or hands when they wrapped a rope around them during a tug of war, and the loop of rope squeezed closed. This has happened more often than one might think, but I’m not aware of anyone who has lost an arm from the sheer force of the pull during a tug of war.
I wondered about that. A snapped rope would mean the force comes towards the person, so unless their arms snapped backwards behind their body and they failed to release their grip… but even then, surely the force is greater than a human grip and would just rip the rope out of their hands. Sure, lovely friction burns, but how would it take the arm off?
Need answer fast?
When you say “friction burns”, you’re thinking of a rope under conditions that one might encounter in everyday life. A rope that breaks under the huge tension in a tug of war behaves differently than any rope you’ve probably ever encountered. The snopes article says the rope in this case was under 80,000 kg of force. All that stored energy has to go somewhere, and most of it goes to accelerating the rope. Just as a ball park estimate, let’s assume that at the time the rope broke, all of this force then went into accelerating 200 pounds of rope. Since F=ma, the rope would be accelerated at about 8600 m/s[sup]2[/sup]. Say it experienced this acceleration for 1/2 second. It would then be moving (v=at) at 9600 miles per hour! A bullwhip can easily break human skin even though it’s only moving at a few hundred miles per hour. (A cracked whip somewhat exceeds the speed of sound, but a whip striking a person must be rather slower than that.) Imagine a whip moving 10 to 20 times faster than a normal whip, with therefore 100 to 400 times the kinetic energy. It would slice through a person’s arm like a sword.