IYPT 1996, Задачи на турнира — Задача 4. Self formation of a pile

9th IYPT (1996)

Заглавие в източника

Source: Turnaj mladých fyzikov : štatút a úlohy, 1996, 37—39
Selected shortly before Dec. 1995
Exemplary solutions for 1996 →

Условие

A horizontal rigid plate vibrates vertically at a frequency of the order of 100 Hz. A cone-shaped pile of fine dispersed powder (e.g. lycopod or talc) which is heaped up on the plate remains stable at small amplitudes of the vibration. If the amplitude is increased the cone decays. Further increase of the amplitude yields a distribution confined by a sharp border and at still higher amplitudes a pile appears again. Investigate and explain this phenomenon.

Решение

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Оригинал в Архива: 1996.txt