Could Indiana Jones swing across chasms using his bullwhip? (continued)

 

Wrap a rope around a tree with a high coefficient of friction (COF) several times, have a football team pull on one end of the rope, and  a child pull on the other; the child can hold the football team in place. The harder the team pulls the higher the friction force resisting the football team becomes. Wrap the same rope around a low COF surface like a flag pole and the team is likely to win.

Likewise if a whip wraps tightly around an object with a high COF several times it will take very little resistance force on the end of the whip to suspend an archeologist from the opposite end. In this case the force previously provided by the child has to come from numerous small sharp protrusions in the wrapped object that essentially "bite" into the braded leather of the whip like small teeth. Being able to swing on a whip is conceivable but not likely. If a person did successfully swing on the free end in an emergency situation, the whip would have to be left behind. There would be no easy way to un-snag a whip wrapped firmly enough to swing on. Certainly pulling on it wouldn't help. Also, getting it snagged firmly enough in the first place is problematic.

 

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For the moment lets ignore the problems of attaching the whip and assume it has been successfully done. If Indianan Jones used a ten foot whip (the most common size used in the movie), wrapped 2 ft of the whip around a tree branch, and swung through a 60 degree arc, he  would be able to swing across an 8 ft (2.4 m) wide chasm. Since the whip would have to suspend Indy's weight and provide enough centripetal force to keep him traveling in an arc, the maximum tension in the whip would occur at the bottom of the swing and be a little over 25% greater than Indy's weight. While such a swing might be possible, why bother? He could run and jump across an 8 ft wide chasm. The best Indy could do is swing through a 180 degree angle which would extend the whip 16 ft in a horizontal direction, but the maximum tension in the whip would now be almost 3 time Indy's weight. He's going to have trouble holding on. Besides how's he going to make a landing? He's going to be in a nearly horizontal position when he reaches the other side. In the end, whip swinging is not going to be either practical or reliable.

Practitioners of Parkour (an escape or running discipline in which participants practice overcoming barriers) have pretty much demonstrated that any chasm that can be crossed by swinging over on a typical bullwhip can much more reliably be crossed by jumping. The discipline was founded by David Belle whose many demonstration videos can be found on YouTube. Okay, Indy might be a little old for Parkour but our bet is that he could still make it across a 10 to 12 foot wide (3m) chasm even without the whip.

As a weapon, a whip has merit for backing off and intimidating multiple would-be robbers or assailants in an open area. The whip can inflict nasty cuts or wrap around an attacker's legs and trip him. However, in close quarters or against a committed attacker armed with weapon such as a sword, spear, or staff, who's willing to take a few painful cuts in order to close distance, a whip is not going to be effective. What's more, it takes relatively little clothing to protect against whip induced injuries. A  heavy raincoat, leather gloves,  and a good motorcycle helmet would offer almost complete protection. As weapons go, we have far more confidence in Indy's revolver than in his whip.

Although there aren't a lot of reasons for an archeologist to carry a whip, we do have to admit that there's something very cool about cracking one.

 


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