1、 - 1 - 06 1 2017 A B v0 C B C B C A C C A B C C L C A C C ft=mv2 mv1 - 2 - C 2 18 m v0 m0 h (1) n (2) 1 (3) f 2 n E E 3 f 0 2 0 2 1 W E h 1 - n n . h 3 - n h 2 - n h 1 - n g m mv mgnh E- 3 - fh fh fh fh W n 1 f 2 . 4 2 3 fh 1 - 2 - E - gh m mv mgnh E n 0 2 1 - n n 2 0 2 1 3 3. F 49 m k d 1 1 2 49 2
2、1 2 d F-2kmg d= 1 2 - 1 2 mv22 3 2 ( 5 3 F m -3kg)d 1 2 3 2m v2 3 1 2 3 d F-3kmg d= 1 2 mv3 2 - 1 2 mv3 2 - 4 - v3 2 = 4 3 ( 7 3 F m -6kg)d v49 2 = 50 49 ( 50 49 3 F m - 50 49 2 kg)d 49m v49 50 v50= 49 99 1225 50 3 dF kg m 49 49 99 1225 50 3 dF kg m v50,0 F 1225 33 kmg. F50kmg. 4. n s 1 v0 2 3 1 n v
3、n 2 1 n 2 1 t1= 0 s v 1 2 mv0=2mv1 v1=v0/2 - 5 - 1 2 3 t2= 1 s v=2 0 s v 1 2 3 4 t3= 2 s v=3 0 s v n-1 n tn= 2 n s v = n-1 0 s v 1 n t= t1+ t2= n= 1+2+3+ n-1 0 s v = 2 n n-1 0 s v 5 M m v v v v v v v v ) v v v 5 m/s v 4 m/s M 30 kg m 10 kg (1) (2) ( lg2 0.301 lg3 0.477) (2) (n 1) vn 1 (n 1) vn 1 Mvn
4、 1 mv (M m)vn 1 n vn Mvn m(vn v (M m)vn 1 - 6 - vn (v v 1 M M m n 1 mv M m M M m n 1 vn v M M m n 1 (M m)v Mv (M m)v n lg Mv (M m)v (M m)v lg M m M 3 v4 5.625 m/s Mv1 m(v1 0 v1 M m 1 m/s Mv1 mv (M (M Mv2 m(v2 v2 (M m) M m 3 m/s Mv2 mv (M Mv2 mv M m (M Mv3 m(v3 v3 (M m) M m 4.5 m/s Mv3 mv (M Mv3 mv M
5、 m (M Mv4 m(v4 v4 (M m) M m 5.625 m/s 3 5.625 m/s (1)2 m/s (2)5.625 m/s 3 6. 2016 A B 2m 3m A 0 v B - 7 - B t m 0 2v A B B 10 1 5 vv 20 4 5 vv 30 1 10 vv B 2 2 3 3 2 3 3 （ ） m v mv m m v 30 1 10 vv 7. 2017 C l 2 m m 2 m A B A C B 2v - 8 - A B A B C g i B C B C C ii A C A i 2 ag ii 2 4 32 2 v v gl 8.
6、 2017 8 10 A B C BC C B A v0=10m/s B A B C 4m/s B C mB=4kg mC=1kg - 9 - i A ii A B i 2kg ii 50J i mAv0= mB+mC v mA= 2kg ii B A u B C BC mBu= mB+mC v u = 5m/s A B 1 2 mAv0 2 = 1 2 1 2 mBvu 2 = 1 2 =50J 50J 9 2 A B C A B C A m B C M A m M A B C ( 5 2) mM A v A C 12 mv mv Mv 2 2 2 12 1 1 1 2 2 2 mv mv
7、Mv - 10 - 1 mM vv mM 2 2m vv mM A B 1 0 v mM A B 1 3 4 mv mv Mv 2 2 2 1 3 4 1 1 1 2 2 2 mv mv Mv 31 mM vv mM 41 2m vv mM mM A 32 vv 2 21 2 () m M m m M v v v v m M m M m M 22 4 m Mm M ( 5 2) mM 10. m0 v0 l m1 l m2 m3 mn 1 n vn 2 a. 1 v1 vn b. n 1 2 n m vn 2 - 11 - n vn =( n 0 m m ) 2v0 2 +2 -1 2 =0
8、2 n n i i m m gl 1 2 mnvn = 1 2 n m ( m0 2 v0 2 +2gl -1 2 =0 n i i m ) 11. 22 abc ab bc ab R=0.30m m=0.20kg A M=0.60kg v0=5.5m/s B A A c b R l 2 4 g=10m/s 2 1 A B 2 B c - 12 - 22 1 v1 A v2 B 1 v A t A R t v 2 4 1 R gt 2 2 1 2 2 1 2 1 2 1 2 1 ) 2 ( mv v m R mg 2 1 0 Mv mv Mv Rg M m v v Rg v 3 2 3 2 0
9、 2 1 s m v / 6 1 s m v / 5 . 3 2 12 20 m h 1 M - 13 - l h 2 m 1.0 10 3 kg M 2.0 10 3 kg h 2.0m l 0.20m g 10m/s 2 F v1 gh v 2 1 h l ) ( 2 2 l h g v V 2 1 mv MV mv Fl Mgl MV 2 2 1 ) ( 2 2 ) ( l h h l h M m l mg Mg F 5 10 1 . 2 F N 13 22 B C A B A B C A B C B C B C A C A C A C - 14 - B C A C C C 22 A B C m A B v0 B C v1 B C mv0 2mv1 A C v2 A B C 2mv0 3mv2 A C A C C s B C 2 1 2 2 ) 2 ( 2 1 ) 2 ( 2 1 v m v m mgs C l A 2 2 2 0 2 1 2 1 ) ( mv mv l s mg 3 7 l s
