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现在有一种“手机自生能”技术．手机上装有特制电池，上下摇晃手机即可产生电能．这种装置实质是将______能转化为电能．如果将手机上下摇动一次，相当于将200g的物体举高l0cm．由此可知，每摇动一次可以获得的电能为______J（假设能量全部转化）．若每秒摇动两次，则摇动手机的功率为______W．

答案

手机通过摇晃产生电能，故应为将机械能转化为电能．

人将物体举高时产生的能量为：W=Gh=mgh=0.2kg×10N/kg×0.1m=0.2J．则可知手机获得的电能为0.2J．

两次摇动手机，手机获得的动能为2×0.2J=0.4J，则功率P=

W
t
=
0.4J
1s
=0.4W．

故答案为：机械能，0.2，0.4

选择题

在育种上要得到更多变异，最好采用[ ]

A．单倍体育种

B．多倍体育种

C．杂交育种

D．诱变育种

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单项选择题

Americans have a great love for informality and nowhere is this better expressed than in their love for nicknames (昵称，绰号). Upon greeting strangers for the first time they will quickly introduce themselves by their nickname. These are shortened forms of their given name at birth and reflect the casual relationships which exist among friends and coworkers. Family names are hardly ever used in daily situations and the use of one’s father’s last name is saved only for rare and formal occasions.
In many traditional cultures the use of the family name is seen as a sign of respect. For Americans, however, it’s the nickname which creates an immediate intimacy between two people upon which to build a relationship. By speaking to another on a first name basis and using his nickname, walls are immediately torn down and equality between two people is established.
At work bosses will refer to their employees by their nicknames. Should an employer use a worker’s family name, you can be sure that some kind of correction or serious business will follow.
This love for nicknames can create a sense of closeness between people who are otherwise not related. Even the presidents of the United States have borne nicknames. Abraham Lincoln was known as Honest Abe. John F. Kennedy was known as Jack or JFK and William Clinton has no reservations in letting people know he prefers to be called Bill, but those who look upon him with disfavor may call him Slick Willy.
Not only people but cities often carry their own nicknames. Chicago is called the "Windy City" because of the p winds which come down from Canada throughout the year. New York City is considered the "Big Apple" for reasons which are still obscure to most people including many New Yorkers.
Not every nickname, however, is positive and some can be rather rude and insulting. If someone should demonstrate a certain negative characteristic, a label will soon be attached to describe that person in an unpleasant way.
Likewise a person’s physical traits which are very dominant may lead to nicknames but not necessarily to one’s liking or choice. A nickname, therefore, is a way of identifying or describing someone or something for better or worse.

Many traditional societies see the use of one’s family name as a sign of ______.

A. respect
B. distance
C. importance
D. gratitude
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