问题 计算题

随着人们生活水平的提高,轿车已逐步进入我国普通百姓家中.下表列出是鬃型小汽车的有关数据.

(1)若该汽车运行100km,则需要油费多少元?

(2)假若该汽车在水平路面上以额定功率做匀速直线运动,速度为90km/h.请计算该车10min内牵引力所做的功.

答案

解:(1)∵V=10L=10×10﹣3m3=1×10﹣2m3

∴汽车行驶100km耗油质量为:

m=ρV=0.75×103kg/m3×1×10﹣2m3=7.5kg

而汽油的价格为7.8元/kg

∴油费为:7.8元/kg×7.5kg=58.5元.

(2)∵P=40kW=4×104W,t=10min=600s

∴牵引力所做的功为:

W=Pt=4 ×104W×600s=2.4×107J

阅读理解

Old age may not sound exciting.But recent findings offer good news for older pepole and for people worried about getting older.

Researches found that people become happier and experience less worry after they reach the age of fifty.In fact,they say by the age of eighty—five,people are happier with their life than they were when they were eighteen years old.

The findings came from a survey of more than 340,000 adults in the United States.The Gallup Organization questioned them by telephone in 2008.At that time,the people were between the ages of eighteen and eighty—five.The searches asked questions about emotions like happiness,sadness and worry.They also asked about mental or emotional stress.

Arthur Stone in the Department of Psychiatry and Behavioral Science at Stony Brook University in New York led the study.His team found that levels of stress were highest among adults  between the ages of twenty—two and twenty—five.The findings showed that stress levels dropped sharply after people reached their fifties.Happiness was highest among the youngest adults and those in their early seventies.The people least likely to report feeling negative emotions were those in their seventies and eighties.

The study also showed that men and women had similar emotional patterns as they grew older.Hower,women at all ages reported more sadness,stress and worry than men.Researchers say they do not know why happiness increases as people get older.One theory is that,as people grow older,they grow more thankful for what they have and have better control of their emotion .They also spend less time thinking about bad experiences.

The researchers also considered possible influences like having young children,being unemployed or being single.But they found that influences like these did not affect the levels of happiness and well—being related to age.

小题1: How did the researchers find older people happier?

A.They did a series of experiments.

B.They made a written survey about the old people.

C.They interviewed people of different ages face to face.

D.They telephoned people between the ages of 18 and 85.小题2:When do people feel happier according to the passage?

A.In their twenties

B.In their fifties

C.After their seventies

D.When they were born小题3:Which one is NOT related to the happiness of old people?

A.Less stress

B.Away from working

C.Controlling of emotions

D.More thankfulness小题4:Which is the best title for the passage?

A.No Worrying about Getting Older

B.Older Men are Happier than Older Women

C.The Factors Affecting the Happiness of Old people

D.For Lots of people,Getting Older Means Getting Happy

单项选择题