问题描述：
英语翻译
forces of 5N,2N and 12N,all lying in the same plane,act on an object.the 5N and 2N forces lie on opposite sides of the 12N force at angles of 40° and 20°,respectively.find the magnitude and direction of the resultant.
forces of 5N,2N and 12N,all lying in the same plane,act on an object.the 5N and 2N forces lie on opposite sides of the 12N force at angles of 40° and 20°,respectively.find the magnitude and direction of the resultant.
问题解答：
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