In order to hold the open door in the metro lobby (the door opens in both directions and returns to the balance position with springs), you need to apply a force of about 50? To the door handle. Can the door be opened by applying a force of 0.005N to the handle? (Ignore friction in the door hinges).
It is possible if you periodically press with a force of 0.005 N with a frequency equal to the frequency of oscillations of the door on the springs.
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