[Пятница][Британские учёные]Велосипед
Помнится, на ЛОРе как-то была дискуссия, мол, почему велосипед не падает, в качестве основной гипотезы выступал гироскопический эффект. И вот, наконец-то, спустя 200 лет после изобретеия, американские и голландские учёные выяснилили, что гироскоп тут ни прри чём, виной всему комплекс физических эффектов.
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To prove that gyro and caster effects were not needed, the researchers built a riderless bicycle with two small wheels, each matched with a counter-rotating disk to eliminate the gyro effects, and with the front wheel contact point slightly ahead of the steering axis, giving it a negative caster effect. When launched at more than about 5 mph, the research bike – like many bicycles – still balanced itself. If you knock it slightly to one side, it straightens itself back upright.
«We have found that almost any self-stable bicycle can be made unstable by misadjusting either the trail, the front-wheel gyro or the front-assembly, center-of-mass position,» the researchers explained in their paper. «Conversely, many unstable bicycles can be made stable by appropriately adjusting any one of these three design variables.»