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J. Perelman
"Entertaining physics". Book 2.
Chapter 3. Circular motion


Many amazing tricks a variety of programs jugglers based also on the properties of rotating bodies to maintain the direction of the axis of rotation. Let me give you an excerpt from a fascinating book English physics Professor John Perry "Spinning top."

"Once I showed some of my experiences in front of an audience, drank coffee and smoked tobacco in a magnificent room in the concert hall "Victoria" in London. I tried to interest my listeners as I could, and was told that the flat ring is necessary to inform the rotation, if willing to throw so that it was possible to specify in advance where it falls; similarly, do, if you want someone to throw his hat so that he could catch this thing stick. You can always rely on the resistance, which has a rotating body, when changing the direction of its axis. Next, I explained to my audience that polished, smooth barrel of the gun, you can never rely on the accuracy of the sight; therefore now make rifled barrels, i.e., cut on the inside of the barrels of guns spiral chute, which are the projections of the core or the shell, so that the latter must receive rotational motion when the force of the explosion causes it to move through the channel of the gun. Due to this, the projectile leaves the gun with a precisely defined rotational movement.

It was all I could do during this lecture, because I don't have the dexterity in throwing hats or disks. But after I finished my lecture, on stage and performed two jugglers, and I couldn't wish for a better illustration of the above-mentioned laws than that which gave each a separate focus, shows these two artists. They threw each other rotating hats, hoops, plates, umbrellas... One of the jugglers threw into the air a number of knives, caught them again and again was thrown with great accuracy up; my audience, just listened to the explanation of these phenomena, were elated with pleasure; she had noticed the rotation, which juggler reported each knife, holding it in her hand so that she could probably know what position the knife back to him. I was amazed that almost without exception all juggling tricks shown that night was an illustration of the above principle.

The coin is tossed without rotation falls in a random position.

As flies coin tossed with rotation.

Planted hat easier to catch if it was reported rotation about an axis.

Entertaining physics J. Perelman


System Orphus


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