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J. Perelman
"Entertaining physics". Book 1.
Chapter 4. Rotation. "Perpetual motion machines"


How to be, if you want, without breaking the shell, define, cooked egg or is it raw? Knowledge of mechanics will help you successfully get out of this little predicament.

The fact that eggs boiled and raw spinning out the same way. This can be used to resolve our problem. Test egg lay on a flat plate and two fingers tell him rotational movement

How to tavertet egg.

Brewed (especially hard-boiled) egg rotates significantly faster and longer raw. The latter is difficult even to turn; meanwhile, cool boiled egg spinning so fast that its outlines are merged eye in white flattened ellipsoid and it should stand up to the sharp end.

The reason for these phenomena lies in the fact that cool boiled egg rotates as a solid whole; cheese in the egg liquid, its contents are not immediately receiving rotational motion, delays due to their inertia, the motion of a rigid shell; it plays the role of the brakes.

Boiled and raw eggs are also different and to stop rotation. If rotating boiled egg to touch it with your finger, it stops immediately. Raw egg, pausing for a moment, after subtracting the hands a little more spin. This is again due to the inertia of the internal fluid mass of cheese in the egg continues to move after the solid body came to rest; the contents of the same boiled eggs stops simultaneously with the stop of the outer shell.

Such tests can be performed and otherwise. Fit raw and boiled eggs rubber rings “Meridian” and hang on two identical strings.

How to distinguish a boiled egg from a raw in their rotation in a suspended state.

Tighten both twine same number of times and release. Once you find the difference between cooked and raw egg. Boiled, coming in the starting position, begin by inertia to spin the thread in the opposite direction, then spin it, and so several times, gradually reducing speed. Raw egg will turn once, twice and stop long before calm down a hard-boiled egg: the movements are inhibited liquid content.

Entertaining physics J. Perelman


System Orphus


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