四、作图题 五、计算题 1解 (1)∑=0x F 0=Ax F (2分)
(2)∑=0y F F F Ay = (2)∑=0A M 0=-+Fd M M A
(a )(b ) 由图(a )可得:
∑=0x F 0=Bx F (2分)
∑=0)(i B F M 0=RC F (2分)
四、作图题 五、计算题 1解 (1)∑=0x F 0=Ax F (2分)
(2)∑=0y F F F Ay = (2)∑=0A M 0=-+Fd M M A
(a )(b ) 由图(a )可得:
∑=0x F 0=Bx F (2分)
∑=0)(i B F M 0=RC F (2分)