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【简答题】
汽车给我们的生活提供了便利，某汽72km/h的速度在平直公路上匀速行驶30km消耗了汽油2kg. (1)请计算2kg汽油完全燃烧，放出的热量．(q 汽油 ＝4.6×10 7 J/kg) (2)已知72km/h的速度匀速行驶时，牵引力的功率为12kW，求汽车受到的阻力． (3)查阅资料可知：汽油机效率最高约为40%;某型号电动机的额定电压为220V，额定电流为10A，正常工作1min所做有用功是1.056×10 5 J，求这台电动机的效率．再具体说一说与汽油机相比电动机的优势．（结合题中信息和生活经验各写一条）
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【单选题】关于产生感应电流的条件,以下说法中正确的是
A.
导体在磁场中运动，导体中就一定有感应电流
B.
导体做切割磁感线运动，导体中就一定有感应电流
C.
穿过闭合电路的磁通量不为零，闭合电路中就一定产生感应电流
D.
无论什么方法，只要穿过闭合回路的磁通量发生变化，闭合电路中就一定产生感应电流
【单选题】Boy:How do you like your new school? Girl:I’m feeling great in my mew school. There are many interesting subject here. ( ) What’s the girl’s attitude towards her new school life?
A.
Positive.
B.
Pressed
C.
Disappointed
D.
Negative.
【简答题】词形填空。 1. How many ______ (teacher) are there in your school? 2. I have three _______( watch ). 3. There are some _______( orange) on the table. 4. Tom is a little _______ ( strong) than Mike. 5. I thi...
【简答题】How many principles are there in subject-verb concord?
【简答题】In the current economic downturn, many American schools are adding a new subject to the curriculum（课程）; financial literacy. One program in Virginia even gets students out of the classroom for a day to...
【单选题】Boy:How do you like your new school? Girl:I’m feeling in my mew school. There are many interesting subject here. ( ) What’s the girl’s attitude towards her new school life?
A.
Positive.
B.
Pressed
C.
Disappointed
D.
Negative.
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