问答题

以下四种说法，哪一种是正确的() A 力在平面内的投影是个矢量力对轴之矩等于力对任一点之矩的矢量在该轴上的投影力在平面内的投影是个代数量力偶对任一点O之矩与该点在空间的位置有关

答案：答案：B 力对轴之矩等于力对任一点之矩的矢量在该轴上的投影解析：A. 力在平面内的投影是个代数量。这个说法是错误的，...

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