Mathematical and Physical Journal
for High Schools
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Problem P. 4299. (December 2010)

P. 4299. A thin, solid uniform rod of length L is placed into a right-angled corner of a wall, and its point A at the bottom of the rod is moved at a uniform velocity of vA, such that the rod always remains in the plane which is perpendicular to the wall and the floor. How far will the bottom end of the initially vertical rod be from the wall, when the top end is disconnected from the wall? (Data: vA=3.5 m/s, L=2 m.)

(5 pont)

Deadline expired on January 10, 2011.

Sorry, the solution is available only in Hungarian. Google translation

Megoldás. A pálca vízszintessel bezárt szögére az elválás pillanatában a \(\displaystyle \sin \varphi=\root3\of{\frac{2}{3}\frac{v_A^2}{gL}}\) eredmény adódik, ekkor a pálca alsó végének a faltól mért távolsága \(\displaystyle L\cos \varphi=1,\!33\) m.


21 students sent a solution.
5 points:Antalicz Balázs, Bolgár Dániel, Jéhn Zoltán, Koncz Gabriella, Nagy Lajos.
4 points:Batki Bálint, Maknics András, Pataki Bálint Ármin, Sárvári Péter, Szabó 928 Attila, Várnai Péter.
3 points:2 students.
2 points:1 student.
1 point:2 students.
0 point:5 students.

Problems in Physics of KöMaL, December 2010