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一质点受到平面上的三个力F1,F2,F3(单位:牛顿)的作用而处于平衡状态.已知...
一质点受到平面上的三个力F1,F2,F3(单位:牛顿)的作用而处于平衡状态.已知D成120°角,且y=g(x)的大小分别为1和2,则有( )
A.F1,F3成90°角
B.F1,F3成150°角
C.F2,F3成90°角
D.F2,F3成60°角
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