A load with mass m is suspended on a thread wound on the armature axis of a dynamo with a permanent magnet. The thread unwinds from the axis so that the load descends at a constant speed v. The dynamo is closed to resistance R. At what speed will the same load rise upward if the dynamo is connected as an electric motor in a direct current circuit with e. d. with equal to E, and with the same circuit resistance R?

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