1、 2017 (90 16 2 1. _ _ . 2. _ . 3 _ _. _ . 4 _ _ 3.4 10 7 J/kg _ 0.5 kg _ 5. ( ) _. _ . 6 200 g 9.2 3 10 J 50 _J/(kg ) _ 7 10X2=20 1 2 3 4 5 6 7 8 9 10 8 A B C D 2.9 10 7 J/kg 1kg 2.9 10 7 J 9 . ( ) A. B. C. D. 10 35% 25% A B C D 11 A B C D 12 A B C D 13 A B C D 14. ( ) A. B. 0 0 C. D.30 20 15. 2 kg
2、10 min ( ) A.5.04 5 10 J B.4.2 5 10 J C.2.52 5 10 J D. 16 ( ) A B C D 17 , A B C D 10+6+2+2 18 10 . (1) _ (2) _ _ (3) _( ) _ . 19 6 8 . 1 2 3 1.4A 8 20. 2 , , . 21 2 .( 18 8 0 1 2 3 0 0.2 0.4 0.6 + 0.6 3 22 9 10 kg . 6 min 0.2 kg 4.2 3 10 J/(kg ) 3 7 10 J/kg. (1) (2) 6 min (3) . 23 9 30cm 2 50mm 9.0 10 5 Pa 1min 1800 1 2 3 16 2 1. . 2. . 3 . . 4 1kg 3.4 10 7 J 1.7 10 7 J 5. . 6 0.92 3 10 J/(kg ) 1kg 1 0.92 3 10 J 7 10X2=20 8 9 10 11 12 13 14 15 16 17 D D D D A A C C B C 10+6+2+2 18 10 . (1) (2) (3) . 19 1 2 0.6 2 3 3 20. 21. 18 22. (1) 6 10 6 J(2)2.52 10 6 J(3)42%. 23 1 2700N 2 135J 3 2025W