1、 8 2018 90 100 ( 10 , 1 , 26 ) 1 . _ _ 2 _ _ . 3 , 0.8mA= A= A 4 5 a b _ _ . 6 ; 1200r/min , . 7 1.2 10 7J/kg 700 g 20 20 8 8 S Sl S2 S Sl S2 9 s a L1 L2 L2 A 10 S L1 L2 L1 I1 L2 I2 I1 I2 = L1 L2 ( 3 ,9 , 27 ) 11 12 13 14 15 16 17 18 19 11 A B C D 12 A. B. C. D. 13 A B C D 14 2 5 3 2 ( ) A.5 3 B.3 5
2、 C.15 4 D.4 15 15 A B A A B A B A B A A B B A A C B A A B D A B A B 16 S A B L1 C L2 D L1 L2 17 A B C D 18 S1 S2 S1 S2 S2 A B C D 19 S 0 A B 1 C. D 2 ( 2 , 28 ) 20 0.5A 1 2 3 _ _ 4 _ _ 21 10g 1 2 4.2 10 3 J (kg ) 3 3.0 10 7 J kg 10g J 22 L1 L2 B A C A C 1 _ 2 L2 _ 3 AB BC AC _ 4 _. ( 23 4 , 24 6 , 2
3、5 9 , 19 ) 23 S A1 0.5A A2 0.4A A3 0.7A L1 L2 L3 A 24 50 kg 10 50 4.2 10 3 J kg 1 ? 2 2.8 10 7 J ? 3 2.8 10 7 J ? 3.5 10 7 J kg 25 72km/h 1500N 150km, 12L 4.2 10 7 J/kg, 0.72g/cm 3 1 2 3 2017-2018 90 100 ( 1 , 26 ) 1 2 3 36V, 0.8*10 -3, 0.8*10 3 4 , 5 , , 6 , 10, 20, 40 7 8.4*10 6 J, 100 8 L2 L3, ;
4、L1 L2 9 L1 0.9 10 = ( 3 , 27 ) 11 12 13 14 15 16 17 18 19 D B B B A B C C D ( 2 , 28 ) 20 ( 12 ) (1) 2 (2) 2 (3) (4 ) (4) (4 ) 21 ( 2 8 ) (1) ; 2 1kg 1 4.2 10 3 J 3 3.0 10 522 ( 2 , 8 ) 1 2 3 4 , . ( 19 ) 23 (4 )I1=0.2A I2=0.2A I3=0.3A 24 1 Q =cm t - t0 =4.2 10 3J kg 50kg 50 - 10 =8.4 10 6 J .2 2 =Q /Q =8.4 10 6 J 2.8 10 7J=30 3 Q =m q m =Q q=2.8 10 7 J 3.5 10 7 J kg=0.8 kg 25 1 2.25 10 8 J .3 2 3 10 4 W 3 3 62% .3
