在刚体上A,B,C二点分别作用三个力F1,F2,F3.各力的方向如图3-2所示,大小恰好与△ABC的边长成比例。问该力系是否平衡?为什么?
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A.He enjoys finding fault with exams. B.He is sure of his success in the exam.
A. He enjoys finding fault with exams.
B. He is sure of his success in the exam.
C. He doesnt know if he can do well in the exam.
D. He used to get straight As in the exams he took.
胰头癌引起梗阻性黄疸,可见
A. 墨菲征阳性
B. 麦氏点压痛
C. 库瓦西耶征阳性
D. 板状腹
E. 库瓦西耶征阴性
试区别FR=F1+F2和FR=F1+F2两个等式代表的意义。