Apparently you may battle a lion on the San Antonio Zoo. OK, it isn’t that sort of battle—it is a tug of battle battle. There’s a thick rope passing by a gap. On one finish, there’s a lion cub. On the opposite finish of the rope there may very well be three skilled WWE wrestlers. Who wins? Effectively, the wrestlers do not win. However there may be additionally some physics right here.
It is all about friction
A typical tug of battle is not actually about energy—it is about friction. It does not matter how robust you might be if you do not have sufficient friction to maintain your self from sliding. Let me present you. Here’s a pressure diagram for 2 individuals in a tug of battle.
Every puller (individual pulling on the rope) has primarily 4 forces appearing on them. There may be the downward weight which is balanced by the upward thrust of the bottom. For the reason that individual pulls on the rope, the rope pulls on the individual in the wrong way (this due to the two-ended nature of forces). Lastly, there may be the frictional pressure between the individual and the bottom. If nobody is “winning,” all these forces add as much as zero and the individual stays at relaxation. To be able to begin shifting within the profitable path, the frictional pressure should be higher than the pressure from the rope.
This “two-ended” nature of forces signifies that forces are available in pairs and are an interplay between two objects. It does not matter how exhausting the individual on the left pulls on the rope, this similar rope pulls on that individual. So in the event you have been to extend your pull to 1,000 Newtons—that very same rope pulls on each individuals. So the secret is the opposite pressure appearing within the horizontal path: friction.
The utmost frictional pressure relies on two issues. It relies on the kinds of surfaces interacting (perhaps it is the rubber on a shoe interacting with a concrete ground) the place some surfaces simply have extra friction than others. You actually cannot change this half in a tug of battle. The friction pressure additionally relies on the conventional pressure. The conventional pressure is the pressure with which the 2 surfaces are pushed collectively. Within the case of this easy tug of battle above, the bottom pushes up with a pressure equal to the gravitational weight of the individual. Which means heavier individuals could have a higher frictional pressure appearing to assist win a tug of battle.
Oh, word that within the human vs. lion tug of battle the people are on a special floor than the lion. Who has the benefit? It is most likely the lion since she may have uneven floor that might enable her to make use of extra than simply plain outdated sliding friction.
So, it is actually about mass
In case you have two contestants on equal floor with comparable friction supplies, mass issues. If the individual on the left has half the mass of the individual on the proper, they’ll have half the friction. Which means it is fairly robust to beat a heavier puller.
What concerning the lion? This seems to be like a younger lion—she may have a mass of about 120 kg (as much as perhaps 182 kg). A typical large human wrestler might need a mass of round 90 to 100 kg. Three people will most likely have extra mass than a single feminine lion. In all probability. The people ought to have a bonus within the mass.
It is also about rope friction
Wait! This is not a standard tug of battle. The rope is not straight. Did you discover that? This could make an enormous distinction in that it could possibly add one other frictional pressure into play. Let me present you ways this works with a diagram of the rope as seen from the highest the place it passes by the glass.
That little yellow dot is simply a part of the rope. If the rope is at relaxation, then the forces on this a part of the rope should add as much as zero (which I’ve drawn to the facet). And right here is the important thing: The pull from the people and the pull from the lion aren’t in reverse instructions. There is no such thing as a method these two forces can add as much as zero. The wall has to additionally push on the rope (to the up and to the proper as seen within the diagram). This wall pressure is a standard pressure—sure, that very same sort of regular pressure that may produce friction.
Since there’s a regular pressure on the rope, there may also be a frictional pressure. In fact it is a rope rubbing in opposition to easy metal in order that it won’t usually be an enormous frictional pressure. Nonetheless, with a big regular pressure you may also get a major frictional pressure.
However which method does the frictional pressure act? If friction had feelings (which it does not—it is only a pressure), it might need to stay calm. Friction acts in a path to forestall the 2 surfaces from sliding. If the people pull more durable than the lion, the lion will get the advantage of friction in order that the rope does not slide in the direction of the people. Nonetheless, if the lion pulled exhausting the frictional pressure would swap sides.
So, who has the benefit with friction? The benefit goes to the loser (most likely the lion).
If you need an actual honest match between people and a lion then it’s a must to a straight rope. It might even be finest to place some tennis footwear on the lion and have her on cement.