问题
选择题
下列例子中属于利用内能来做功的是（ ）
A．火箭点火发射
B．电热水器给水加热
C．用高炉熔化铁块
D．用热水袋取暖
答案
A、火箭点火后，在“熊熊烈火”的喷射中冲天而起．是内能转化为机械能．
B、电热水器给水加热，是电能转化为内能；
C、用高炉熔化铁块，是热传递；
D、用热水袋取暖，是热传递．
故选A．
搜题请搜索小程序“爱下问搜题”
下列例子中属于利用内能来做功的是（ ）
A．火箭点火发射
B．电热水器给水加热
C．用高炉熔化铁块
D．用热水袋取暖
A、火箭点火后，在“熊熊烈火”的喷射中冲天而起．是内能转化为机械能．
B、电热水器给水加热，是电能转化为内能；
C、用高炉熔化铁块，是热传递；
D、用热水袋取暖，是热传递．
故选A．
God’s Coffee A group of class friends, highly achieved in their careers, got together to visit their old university professor．Conversation soon 31 into complaints about stress(压力) in work and life． Offering his guests coffee, the professor went to the 32 and returned with a large pot of coffee and a couple of 33 —porcelain, plastic, glass, crystal, some plain looking, 34 expensive, some delicate—telling them to 35 themselves to the coffee． When all the students had a cup of coffee in 36 ,the professor said：“If you noticed，all the nice looking expensive cups were taken up, 37 behind the plain and cheap ones. While it is 38 for you to choose only the best for yourselves, that is the 39 of your problems and stress．Be sure that the cup itself 40 no quality to the coffee．In most cases it is just more expensive and in some cases even hides what we drink． 41 all of you really wanted was coffee, not the cup, but you consciously (自觉地) went 42 the best cups．And then you began 43 each other’s cups．Now consider this：Life is the 44 ; the jobs, money and position in society are the cups．They are just tools to hold and contain life, and the type of cup we have does not explain , nor 45 the quality of life we 46 . Sometimes, by concentrating only on the cup, we 47 to enjoy the coffee God has 48 us．God brews the coffee, not the cups…Enjoy your coffee!” The happiest people don’t have the best of everything．They just 49 the best of everything． Live simply．Love generously．Care deeply．Speak kindly．Leave the 50 to God．
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