Задача id9116

A horseshoe-shaped frame АВСС'В'А'А is made of thin wire. If a soap film is formed on it, then the surface tension forces acting on the frame in sections ABC and A'B'C will be horizontal and cancel each other out, and the forces acting on the frame in sections AA' and CC' will be directed upward. Therefore, if the frame is light enough, it will fly. Point out the error in this reasoning.

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