[Daily Question] Theoretical Basis 2020.01.16

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Multiple choice questions: A winch has three handles of equal length L. The three handles are all in the horizontal plane, and the angles between them are all 120°. For example, in the horizontal plane, each handle end acts on a force F1, F2, and F3 perpendicular to the handle, and F1=F2=F3=F. The simplified principal vector and principal moment of this force system towards point D should be (). Answer: B Translate F1, F2, and F3 to point O respectively. According to the translation theorem of force, a plane intersection force system and a force couple system are obtained, as shown. Obviously, the resultant force of the plane intersection force system is zero, and the resultant couple moment of the plane force couple system is 3Fl, and the direction is counterclockwise.: Those who can explain the problem-solving process will be given extra rewards, and the answers will be visible in the replies!