1、 1 ( ) ( 40 ) A 1 ) P Q P Q ( ) A P Q B P Q C P Q D P Q A P Q P Q A v P Q P Q B Q C P Q D 2 ) A B ( ) O rA rB. ( ) A B C FAmQ A B F F mg m v 2 L F 3mg mPmQ FPFQ C a F mg m 2g D 7 ( ) d h ( ) A v0 d g 2hB v0 2d g 2hC g 2hD g 2hAC h 1 2 gt 2 d v0t v0 d g 2h A B t n 1 2 2h g n 0 g 2h n 1 g 2h C D 8 m O
2、 R. 5 O r Rsin G FN FNsin m v 2 Rsin FNcos mg FN mg cos v Rgsin tan . Rgsin tan mg cos B 9 ( m a b( ) a OO l b 2l k g. ( ) 92492183 A b a B a b C kg 2l b D 2kg 3l a kmg AC a b f 2 R. a fa 2 al fa kmg kmg 2 al a kg l 6 b fb 2 b l fb kmg kmg 2 b l b kg 2l b A fa 2 l fb 2 l fafb B kg 2l b C 2kg 3l a fa
3、 2 l 2 3 kmg D 10 ( ) B 0.3 s R 1 m m 1 kg g 10 m/s 2 . ( ) 92492184 A C B 0.9 m B C B 1.9 m C B NB 1 N D B NB 2 N AC C vy gt 3 m/s vx vy 3 m/s B C x vxt 0.9 m A B B NB mg m v 2 B R vB vx 3 m/s NB 1 N C D 11 ) ( R 0.20 m) (a) (b) 7 (1) 1.00 kg (2) (b) _kg (3) m m 1 2 3 4 5 m(kg) 1.80 1.75 1.85 1.75
4、1.90 (4) _N _m/s.( 9.80 m/s 2 2 ) (2) (b) 1.40 kg. (4) m 1.80 1.75 1.85 1.75 1.90 5kg 1.81 kg. F (m 1.00)g (1.81 m (1.40 1.00) kg 0.40 kg F m g m v 2 R v (2)1.40 (4)7.9 1.4 12 ) R 90 m r 40 m O O L 100 m 2.25 ( g 10 m/s 2 3.14) (1) 8 (2) (3) (1) kmg m v 2 m r vmr kgr m/s 30 m/s vmR kgR m/s 45 m/s. (
5、2) x L 2 R r 2 50 3 m v 2 mR v 2 mr 2ax a v 2 mR v 2 mr 2x 45 2 30 2 3m/s 2 2 . (3) q1 q2 r 3 R 3 t1 r 3 vmr t2 R 3 vmR s 8.37 s t3 x vmR vmr 2 t3 t3 2.31 s t t1 t2 2t3 15.79 s (1)30 m/s 45 m/s (2)6.50 m/s 2(3)15.79 s 13 ) R h P P P O L(L R) P ( ) 9 (1) A B AOB (2) (3) ( ) A B v 92492185 (1) P t h 1
6、 2 gt 2 t 2h g A xA vAt L R vA (L R) g 2h B xB vBt L 2 R 2 vB g L 2 R 2 2h . (2) v0min vA (L R) g 2h C x0 v0maxt L R v0max (L R) g 2h (L R) g 2h v0 L R) g 2h . (3) B tAB n 1 4 R v (n 0,1,2,3 tAB t 2h g v 1 2 (4n R g 2h (n 0,1,2,3 (1)vA (L R) g 2h vB g L 2 R 2 2h(2)(L R) g 2h v0 L R) g 2h(3)v 1 2 (4n R g 2h (n 0,1,2,3
