问题 选择题

静止的升降机里挂着一个弹簧秤,秤钩上挂一重物,读数为G;升降机匀速上升时读数为F1;升降机匀速下降时,读数为F2;三个读数比较:(  )

A.GF1F2;

B.F1>F2>G

C.F2>G>F1

D.F1=F2=G

答案

答案:D

题目分析:物体无论是静止还是匀速上升、匀速下降,都是平衡状态;物体受重力及钢丝绳的拉力相等。

故选D.

点评:关键是学生对平衡状态的理解,要求明确只要物体做匀速直线运动,物体即处于平衡状态.

阅读理解

Amanda Clement grew up in Hudson,South Dakota.Baseball was always her favorite sport.Once in a while her brother Hank and his friends would let her play first base in their games.More often,however,they asked her to umpire(裁判)for them, because they knew her calls would be fair and there would be no arguing.

One day in 1904,Amanda and her mother traveled to Hawarden,Iowa,to watch Hank play for the home team against Hawarden.When they arrived at the ball field,two local teams were waiting to play a preliminary(预备)game.The umpire hadn’t arrived,so Hank argued that the teams should let his sister serve as umpire.The players finally agreed.

Amanda,then sixteen and standing five feet,ten inches tall,made perfect calls.

She was so good that players for the main game asked her 10 umpire for them and even

offered to pay her.Thus,at sixteen,Amanda Clement became the first paid female

baseball umpire on record.She is honored in the Baseball Hall of Fame in Cooperstown,

New York.

小题1:Hank and his friends often asked Amanda to umpire for them because      

A.they wanted to make her happy

B.she called them brothers

C.no one else wanted to do it for them

D.she knew the rules well and was fair小题2:Amanda went to Hawarden in order to      

A.serve as umpire

B.make money

C.watch her brother play

D.help the local teams小题3:Amanda most probably learned how to umpire a baseball game       .

A.in her P.E.classes at school

B.in an umpire training school

C.by watching and playing the games

D.from her mother,a baseball umpire小题4:Which of the following can be the best title of the passage?

A.Amanda Clement.First Female Umpire

B.A Family of Baseball Fans

C.Baseball Games in Hawarden,Iowa

D.The Baseball Hall of Fame in Cooperstown

单项选择题