1、 / 5 1 02 4 A B 2 C 4 D 2 A 12 2 QQ Fk r 4 1 2 1 2 22 44 16 16 Q Q QQ F k k F rr C 12 2 QQ Fk r 2 1 2 1 2 22 2 22 Q Q QQ F k k F rr D 1 1 2 2 2 1 r q q k F k k 9 2 /C 2 3 / 5 2 2 1 2 2 1 r q q k F F =0 Fx=0 Fy=0 2 3 4 1 2 F 3 A 3 FB 3F C 9 FD 9F A B L A 2Q B +4Q F A B 2L A B A 4 FB 32 FC 8 FD 9 8 F
2、A B +2q 6q r F 2 r / 5 3 A 4 3 FB 3 4 FC 2 FD 2F A B A B A B C D M N Q q F A Q q B Q q C 2 Q q 1 4 F D 2 Q q 4F Q A Q P B A B A B P A B C D m A B C L A qA=+10q B qB=+q C F L 1 C / 5 4 2 F B 2 22 2 4 8 = k Q Q kQ F LL 2L +Q 22 2 2 = 4 32 2 kQ kQ F F L L B A r 2 26 qq Fk r 26 2 2 qq qq 2 22 () 2 qq Fk r 4 3 FF A BCD C 12 2 qq Fk r AB C ABD BC Q q Q q A B 2 kQq F r 2 Q q 1 4 F C D A G A F1 F2 F1 F2 F F=G FF1B PBQ 1 FF FB PQ PB 2 PB FG PQ / 5 5 A B PB PQ G F2 A BCD 1 2 2 2 70 q k L 1 A B C A B C 2 a F=3ma A B A 22 4 AC AB kq q kq q ma LL B 22 BC AB kq q kq q ma LL F= 2 2 70 q k L
