Cím:	Problems of the 1999 Eötvös Physics Competition
Füzet:	2000/április, 256. oldal	PDF  |  MathML
Témakör(ök):	Eötvös Loránd (korábban Károly Irén)

A szöveg csak Firefox böngészőben jelenik meg helyesen. Használja a fenti PDF file-ra mutató link-et a letöltésre.   1. A fighter plane flies horizontally above us at a height of 0.9 km. It is at a distance of 1 km from us when we first hear its sound. From what direction do we hear its sound when it is at a distance of 2 km from us?   2. The neck of one of two otherwise identical flasks is straight, that of the other one bends downwards as shown in the figure on page 242). Identical quantities of $A)$ water and $B)$ ether are poured into the flasks, making sure that the temperature of the liquid is $100{}^{\circ }$C in case $A)$ and $34\mathrm{.}6{}^{\circ }$C in case $B)$. From which flask is the liquid first off in case $A)$ and in case $B)$?   3. A long, thin, vertical glass tube is surrounded by a much thicker, coaxial glass tube of diameter $D$. There are closely spaced, short-circuited one-turn coils of resistance $R$ each at distance $h$ of each other on the thick tube (see the figure on page 243). A small rod magnet of mass $m$ and dipole momentum $d$ is dropped into the thin tube; it reaches a constant speed $v_0$ after a relatively short time interval. How many times the original would the speed of the magnet be if $a)$ the mass of the magnet, $b)$ the dipole momentum of the magnet, $c)$ the distance between the turns, $d)$ the resistance of the turns, $e)$ the diameter of the turns were changed to twice the original value without changing the other data? Mechanical friction, air resistance, the self- and mutual induction of the turns can be neglected.