问题 实验题

图甲所示为粗略测量某机器转动角速度的实验装置,半径不大的圆形卡纸固定在机器的转轴上,在机器的带动下匀速转动,在圆形卡纸的旁边垂直安装一个改装了的电火花计时器。

(1)请将下列实验步骤按先后排序:__________。

A.使电火花计时器与圆形卡纸保持良好接触

B.接通电火花计时器的电源,使它工作起来

C.启动机器,使圆形卡纸转动起来

D.关闭机器,拆除电火花计时器;研究卡纸上留下的一段痕迹(如图乙所示),写出角速度ω的表达式,代人数据,得出ω的测量值

(2)要得到ω的测量值,还缺少一种必要的测量工具,它是下面的__________。

A.秒表

B.毫米刻度尺

C.圆规

D.量角器

(3)写出角速度ω的表达式______________。

(4)为了避免在卡纸连续转动的过程中出现打点重叠,在电火花计时器与盘面保持良好接触的同时,可以缓慢地将电火花计时器沿圆形卡纸半径方向向卡纸中心移动。则卡纸上打下的点的分布曲线不是一个圆,而是类似一种螺旋线,如图丙所示,这对测量结果有影响吗?__________

答案

(1)ACBD

(2)D

(3)

(4)没有影响

单项选择题 A1/A2型题
阅读理解

Two elderly women in my community died "full of years,"which means both died from the normal wearing out of the body after a long and full life. Their homes happened to be near each other, so I paid visits to the two families.

The son of one of the deceased(已故的) women said to me,"If only I had sent my mother to Florida and got her out of this cold ,she would be alive today. "The son of the other deceased woman said, "If only I hadn't insisted on my mother's going to Florida, she would be alive today. That long airplane ride, the sudden change of climate, was more than she could take. "

When things don't turn out as we would like them to, it is very likely for us to think that if we had done things differently, the story would have had a happier ending. Any time there is a death, the survivors will feel guilty.

There seem to be two elements in our readiness to feel guilty. The first is our pressing need to believe that the world makes sense and that there is a cause for every effect and a reason for everything that happens. That leads us to try to find the patterns and connections.

The second element is the notion(观念)that we are the cause of what happens, especially the bad things that happen. Psychologists trace this feeling back to our childhood. A baby comes to think that the world exists to meet his needs, and that he makes everything happen in it. The world works for him. When he cries, someone comes to attend to him. When he is hungry, people feed him, and when he is wet, people change him. Very often, we do not completely outgrow the notion that our wishes cause things to happen.

69.What is said about the two deceased elderly women?

A. They lived long and died after a natural life.

B. They died due to lack of care by family members.

C. They died of the tiredness after the long plane ride.

D. They weren't quite used to the change in weather.

70.People feel guilty for the deaths of their beloved ones because_______.

A. they believe that they were responsible

B. they do not know the natural course of events

C. they couldn't find a better way to express their grief

D. they didn't know things often turn out in the opposite direction

71.The underlined sentence "the world makes sense" probably means that_______.

A. we have to be sensible so as to understand the world

B. everything in the world is pre-determined

C. there's an explanation for everything in the world

D. the world can be interpreted in different ways

72.People have been made to believe since babyhood that_______.

A. every story should have a happy ending

B. their wishes are the cause of everything that happens

C. life and death is an unsolved mystery

D. everybody should obey their wills without question