Mathematical and Physical Journal
for High Schools
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# Problem P. 4796. (January 2016)

P. 4796. Two simple pendulums of the same length are suspended at the same point. One of the pendulum bobs is an iron ball of mass 78-g and the other one is a 12-g ball made of modelling clay. The pendulums are displaced such that the angle between the threads is $\displaystyle 60^\circ$, and

$\displaystyle a)$ the angles between the threads and the horizontal are also $\displaystyle 60^\circ$;

$\displaystyle b)$ the angles between the threads and the vertical are also $\displaystyle 60^\circ$.

The two bobs are released at the same instant without any initial speed. The two bobs collide and stick to each other. What is the angle between the threads and the vertical when the two bobs are at the highest point?

(5 pont)

Deadline expired on February 10, 2016.

### Statistics:

 68 students sent a solution. 5 points: Asztalos Bogdán, Balogh Menyhért, Bekes Nándor, Blum Balázs, Di Giovanni András, Fajszi Bulcsú, Fehér 169 Szilveszter, Fekete Balázs Attila, Forrai Botond, Ghada Alshalan, Kasza Bence, Kovács Péter Tamás, Mándoki László, Németh Csaba Tibor, Olosz Adél, Páhoki Tamás, Sal Kristóf, Szántó Benedek, Tomcsányi Gergely, Tóth Adrián. 4 points: Bartók Imre, Édes Lili, Elek Péter, Farkas Domonkos, Gémes Antal, Hajnal Dániel Konrád, Jakus Balázs István, Kluèka Vivien, Molnár Mátyás, Pázmán Előd, Pintér 345 Balázs, Pszota Máté, Radnai Bálint, Tófalusi Ádám. 3 points: 13 students. 2 points: 16 students. 1 point: 4 students. 0 point: 1 student.

Problems in Physics of KöMaL, January 2016