问题 填空题

一乘客在行驶的火车车厢里用细绳吊一小球,用以判断火车运动的情况,并可得到如下结论:

小题1:若小球在竖直方向保持静止,表明火车正在做___________运动;

小题2:若在竖直方向保持静止的小球突然向后摆,表明火车正在做___________运动;

小题3:若在竖直方向保持静止的小球突然向前摆,表明火车正在做___________运动;

小题4:若在竖直方向保持静止的小球突然向右摆,表明火车正在做___________运动。

答案

小题1:

小题2:

小题3:

小题4:

力与运动的关系;匀速直线运动;平衡状态的判断.物体具有保持原来运动状态不变的性质,叫做惯性;任何物体在任何情况下都具有惯性;

①小球静止,说明小球和汽车是相对静止的状态,也就是小球和汽车的运动状态都没有发生改变,而没有发生改变的运动状态是静止和匀速直线运动;

②小球突然后摆,说明车的速度比小球的速度快了,所以车是在加速;

③球突然向前,说明球的速度快于车的速度,所以车是在减速;

④球突然向右摆动,说明车在左转弯;

故答案为:①匀速直线;②加速;③减速;④向左;

阅读理解

Mrs. Blake teaches English in a large school in the inner area of a big city on the west of coast. Even since she was a young girl,she has wanted to become a teacher. She has taught eight years now and hasn‘t changed her mind. After she graduated from high school, she went on to college. Four years later, she received her bachelor’s degree (B A) in English and her teaching certificate(证书)。 Then she went to teach in the secondary schools of her state. In the summers, Mrs. Blake takes more classes; she hopes to get a master‘s degree (M A)。 With an MA, she will receive a higher salary and if possible, she hopes to get a doctor’s degree as well. The school day at Mrs. Blake‘s high school, like that in many high schools in the United States, is divided into one hour each. Mrs. Blake must teach five of these periods. During her free period, which for her is from 2 to 3 P.M. , Mrs. Blake must meet with parents, make out examinations, check assignments at all, Mrs. Blake works continuously from the time she arrives at school in the morning till the time she leaves for home late in the afternoon.

1. How long is it since Mrs. Blake graduated from middle school?

A. four years B. eight years C. twelve years d. twenty years

2. According to the article, which is the right order of the degrees a person can receive after going to university?

A. a doctor‘s degree – a bachelor’s degree – a master‘s degree

B. a bachelor’s degree – a master‘s degree – a doctor’s degree

C. a master‘s degree—a bachelor’s degree – a doctor‘s degree

D. a bachelor’s degree – a doctor‘s degree—a master’s degree

3. How many degrees has Mrs. Blake achieved so far?

A. one   B. two    C. three   D. none

4. Which of the following sentences is not true?

A. Mrs. Blake teaches in the inner area of big city on the east of the United Sates

B. Mrs. Blake has turned her wish of becoming a teacher into reality.

C. Mrs. Blake is still studying in her holidays in order to get higher degrees.

D. The working hours in the school where Mrs. Blake works are similar to those of many other high schools in the states.

判断题