Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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# Problem P. 4816. (February 2016)

P. 4816. A current of $\displaystyle I=25$ A flows in a piece of wide straight wire, which is fixed to a horizontal plane. The wire can be considered infinitely long. Next to the wire at a distance of $\displaystyle r_0=1$ cm from it there is a closed rectangle shaped loop of copper wire on the horizontal plane. The sides of the rectangle are $\displaystyle a=5$ cm, and $\displaystyle b=10$ cm. The current in the straight wire is decreased to zero uniformly in a very short time. What would the speed of the copper loop be if there was no frictional force exerted to it?

(5 pont)

Deadline expired on March 10, 2016.

### Statistics:

 27 students sent a solution. 5 points: Asztalos Bogdán, Balogh Menyhért, Bekes Nándor, Blum Balázs, Büki Máté, Fekete Balázs Attila, Forrai Botond, Ghada Alshalan, Iván Balázs, Jakus Balázs István, Kasza Bence, Kovács Péter Tamás, Sal Kristóf, Szentivánszki Soma , Szick Dániel, Tomcsányi Gergely, Zöllner András. 4 points: Csorba Benjámin, Körmöczi Dávid, Mándoki László, Németh 777 Róbert, Páhoki Tamás. 3 points: 4 students. 2 points: 1 student.

Problems in Physics of KöMaL, February 2016