Physics Cup – TalTech 2021 – Pr. 1, Hint 1.

Electromagnetic plus kinetic energy is not conserved as some of it is converted into heat when current flows between the balls. However, there is another conservation law.

Apart from this hint, a warning: the electrical polarizability of this “dumbbell” is much bigger than that of a sphere. (Several otherwise good solutions had a simple mistake of not noticing this.)

Chinese translation of hint 1 (中文)

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