初中物理练习题四及答案doc.txt

() 1. n s ( ) 2. 磬 ( ) 3. ( ) 4. ? ( ) 5. ? ( ) 6. 嶼 ( ) 7. 12 36 220 380 ( ) 8. 0.251.5 1.75 1.7510 1.210 1.1610 1.010 ( ) 9. ( ) 10. ( ) 11. a b gagb gagb gagb gagb gagb ( ) 12. ($s*a$) 13. ac ad bc bd ( ) 14. ( ) 15. 棬50 50 40 50 40 ( ) 16. ob ( ) 17. ur1 ( ) 18. ( ) 19. ()İ ( ) 20. 顢 (=(7.8)()=2.7=0.4) ( ) 21. “220v 100w“220v 40w“220 100w40w 40w 100w 40w ( ) 22. ( ) 23. 6r10 r050p a b 仯 06 05 01 15 ( ) 1. 嶼( )( ) 2. ( ) 3. 澵( )( ) 4. 1( ) 5. 澵30( ) 6. 220100棬( ) 7. 1“220v 25w“( ) 8. 壬( ) 9. 500壬f5 3(ab()a b( ) bc5 ( ) () 1. h=20s=1.010v=4.010 (1) (2) (3) 1960 19.6 39.2 25.5 (1) ( ) (2) ( ) (3) ( ) (1) p=gh =1.0109.80.2 =1960=1960 (2) f=ps =19601.010=19.6 (3) g=mg=gv =1.0109.84.010 =39.2() 1960 19.639.2 2. 6r2 10r1 0.4 (1) r2 (2) (3) 衣 0.6 2 1 6 (1) ( ) (2) ( ) (3) ( ) (1) r2 i2= = =0.6() (2) i=i1+i2 =0.4+0.6=1 (3) r= = =6() r1= = 15() r = =6() i = = 1() r20.616 1. 3.8 (1) ( ) (2) ( )( )(03 015) (3) ($w*$)( ) 1. c 2. b 3. c 4. a 5. d 6. a 7. c 8. b 9. d 10. d 11. a 12. a 13. b 14. c 15. d 16. d 17.c 18. b 19. a 20. a 21. b 22. c 23. b 1. 2. 3. 飻 4. 5. 60 6. 160 7. 40 8. 9. 15000 1abc (1) p=gh =1.0109.80.2 =1960=1960 (2) f=ps =19601.010=19.6 (3) g=mg=gv =1.0109.84.010 =39.2() 1960 19.639.2 2. acd (1) r2 i2= = =0.6() (2) i=i1+i2 =0.4+0.6=1 (3) r= = =6() r1= =