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J. Perelman
"Entertaining physics". Book 2.
Chapter 8. The magnetism. Electricity


A curious case was observed once when working with electromagnetic crane. One of the workers noticed that the electromagnet was drawn heavy iron ball with a short chain attached to the floor, which did not let the ball get close to the magnet: between the ball and the magnet remained a gap in the palm width. Turned out to be an extraordinary picture: chain, sticking straight up! The strength of the magnet was so great that the chain has retained its vertical position, even when it hung work*. Local photographer hurried to capture on record such an interesting time, and we present here the figure of a man hanging in the air like the legendary Magomedova coffin.

Iron chain with cargo, sticking up.

By the way, about Magomedova the coffin. Devout Muslims believe that the coffin with the remains of the "prophet" rests in the air, hanging in the tomb without any support between the floor and ceiling.

Is it possible? "Tell us, " wrote Euler in his "Letters on different physical things, like the tomb of Mohammed holds the power of a magnet; it seems not impossible, because there are magnets, art made that lift up to 100 pounds**".

This explanation is untenable; if the specified method (i.e., using magnetic attraction) such an equilibrium was reached at one point, the slightest push, the slightest breath of air would be enough to break, and then the coffin or would have fallen on the floor or up to the ceiling. Hold it motionless almost as impossible as to put the cone on top of it, although theoretically the last and valid.

However, the phenomenon of "Magomedova coffin, it is possible to reproduce and using magnets, but only using not their mutual attraction, but on the contrary, mutual repulsion. (That magnets can not only attract, but also to work, often overlooked, even people who have recently studied physics.) As you know, the same poles of magnets repel. Two magnetized bar, arranged so that like poles are one above the other, repel each other; picking up the weight of the upper bar properly, it is easy to get it hung over the bottom, holding on without touching him, in a stable equilibrium. We just have racks of nonmagnetic material - such as glass, to prevent rotation of the upper magnet in the horizontal plane. In such an environment could hover in the air and legendary tomb of Mohammed.

Finally, the phenomenon of this kind is feasible, and the strength of magnetic attraction, if to get his body moving. Based on this thought a great project electromagnetic Railways without friction offered by the Soviet physicist Prof. bpts Veinberga. The project is so instructive that everyone interested in physics it is useful to meet him.

Car racing without friction. The road is designed prof b N Veinberga.

* This indicates the great strength of an electromagnet, because the magnetic action of the magnets znachitelno weakens with increasing distance between the pole and bound body. Horseshoe magnet holding is in direct contact load in a hundred grams, reduces its lift force twice, when between him and the cargo is put a piece of paper. Vogue why the ends of the magnet are usually not covered with paint, although it would've kept them from rust.
**Written in 1774, when the electromagnets were not yet known.

Entertaining physics J. Perelman


System Orphus


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