问题 填空题

2011年安徽省在中招体育测试中,亳州市把跳绳作为考试科目。李强同学在中考体育测试中的跳绳成绩是1 min跳180次.他的质量为50 kg,每次跳起的高度约为6 cm,他跳绳时克服重力做功的平均功率约为_______W.

答案

90

考点:

专题:计算题;应用题.

分析:跳绳过程是克服自身重力做功的过程,根据W=Gh计算1min内所做的功,再由P=求出功率.

解答:解:由题知:m=50kg;h=6cm=0.06m;t=1min=60s;

W=Gh=mgnh=50kg×10N/kg×180×0.06m=5400J;

P===90W.

故答案为:90.

点评:考查功与功率的计算,本题需要注意的是跳绳所做的总功(等于每次所做的功乘以跳绳的次数)与做功的时间.

阅读理解

阅读理解

     One day an Australian farmer, Joe, saw a bright light in the sky.①The light came nearer and nearer and suddenly

Joe saw that it was a spaceship. The spaceship landed in a field quickly.    The door of the spaceship opened and two

strange beings climbed out.②They seemed to be half man and half bird. Joe was afraid of them. He tried to run away.

But the spacemen walked towards him, picked him up and carried him into the spaceship. They put wires(电线) from

a machine onto his head and they could speak to him in English.

     They asked him some questions about the earth. "We are from Venus," they said, "but it's getting very hot there. A

lot of our people are dying and we don't have much time left. We are trying to find a new home."

     After some time they③freed Joe and at last the spaceship took off and could not be seen again. Joe told his friends

about the spaceship, but no one believed his story.

     "You'll believe me one day," Joe told them. "The spaceman will come back..."

1. 翻译①处画线部分句子

    _______________________________.

2. 不改变句意,改写②处句子

    _______________________________.

3. According to the conversation between Joe and the aliens, what do we know about Venus?

    _______________________________.

4. ③处单词的意思是_____

A. let…go

B. paid no money

C. took away

D. locked

5. 用文中的两个词填空。

    (1) Some people _____ in everlasting life after death.

    (2)The girls are _____ of going out at night.

单项选择题