Mathematical and Physical Journal
for High Schools
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Problem P. 3965. (March 2007)

P. 3965. From the top of a rough sphere of radius R a small ball of radius r and of mass m rolls down with no initial speed. Where will the ball begin to slide and what is the frictional force at the moment when it begins to slide if R=1 m, r=0.1 m, m=15 kg, and the coefficient of static friction is \mu=\mu0=0.2?

(5 pont)

Deadline expired on April 11, 2007.


Statistics:

82 students sent a solution.
5 points:Almási 270 Gábor András, Balogh Máté, Blastik Zsófia, Blázsik Zoltán, Bogár 560 Péter, Danka Miklós András, Dudás János, Englert Dávid, Fehér András, Fonyó Dávid, Gudenus Gergő, Hlatky Dávid, Horváth 795 Andrea, Horváth Bence, Iván Dávid, Karsa Anita, Lovas Lia Izabella, Nagy 224 Csaba, Nagy 630 Viktor, Nagy 897 Zsolt, Nagy Zsolt Péter, Pálovics Róbert, Roósz Gergő, Szilágyi Zsombor, Tolnai Gábor, Tolner Ferenc, Tűri Balázs, Tüzes Dániel, Varga Bonbien, Vécsi Áron, Vida György.
4 points:Bodosi Eszter, Domsa Daniella, Najbauer Eszter Éva, Szabó 666 Dániel.
3 points:20 students.
2 points:11 students.
1 point:4 students.
0 point:1 student.
Unfair, not evaluated:11 solutionss.

Problems in Physics of KöMaL, March 2007