卫生类相同项单选集 考试卷模拟考试题_0

1、姓名：_ 班级：_ 学号：_-密-封 -线- 卫生类相同项单选集 考试卷模拟考试题考试时间：120分钟 考试总分：100分题号一二三四五总分分数遵守考场纪律，维护知识尊严，杜绝违纪行为，确保考试结果公正。1、escaping from the earththe earth has a force that pulls things toward itself. we call this force gravity(地心引力). this is something we live with all the time, and we take it for granted and hardly e

2、ver think about it. but it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all.take the throwing of a ball as an example. the harder the ball is thrown, the faster and higher it will go. what is the secret its speed. if we

3、could throw the ball hard enough it would go up and up forever and never come down. the speed at which it would have to be thrown to do this is known as escape speed. of course, we cannot throw a ball hard enough because the speed required to escape completely from the earths gravity is seven miles

4、per second, or over twenty-five thousand miles per hour.once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. a rocket aimed at the moon, for instance, will “coast”(滑行) the rest of the way because the earths gravity cannot then pull it back, and there is no air resist

5、ance(阻力) in space to slow it down. this “coasting” is known as “free fall”. that does not mean the rocket is falling down towards the earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill.free fall is an important feature of space travel: it would

6、be impossible to carry enough fuel to provide powered flight all the time.what is the most important factor for a rocket to escape from the earth（ ）a.to travel as fast as it can.b.to overcome the earth gravity.c.to get away from the air resistance.d.to have strong power in its operation.2、escaping f

7、rom the earththe earth has a force that pulls things toward itself. we call this force gravity(地心引力). this is something we live with all the time, and we take it for granted and hardly ever think about it. but it is a most important factor in rocket operation and must be overcome if we are to get an

8、ywhere in space, or off the ground at all.take the throwing of a ball as an example. the harder the ball is thrown, the faster and higher it will go. what is the secret its speed. if we could throw the ball hard enough it would go up and up forever and never come down. the speed at which it would ha

9、ve to be thrown to do this is known as escape speed. of course, we cannot throw a ball hard enough because the speed required to escape completely from the earths gravity is seven miles per second, or over twenty-five thousand miles per hour.once escape speed has been reached by a spacecraft(宇宙飞船),

10、no further power is needed. a rocket aimed at the moon, for instance, will “coast”(滑行) the rest of the way because the earths gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. this “coasting” is known as “free fall”. that does not mean the rocket is falli

11、ng down towards the earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill.free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all the time.how fast will a rocket go to escape comp

12、letely from the earths gravity（ ）a.seventy miles per second.b.seven thousand miles per hour.c.twenty-five thousand miles per second.d.twenty-five thousand miles per hour.3、escaping from the earththe earth has a force that pulls things toward itself. we call this force gravity(地心引力). this is somethin

13、g we live with all the time, and we take it for granted and hardly ever think about it. but it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all.take the throwing of a ball as an example. the harder the ball is thrown, th

14、e faster and higher it will go. what is the secret its speed. if we could throw the ball hard enough it would go up and up forever and never come down. the speed at which it would have to be thrown to do this is known as escape speed. of course, we cannot throw a ball hard enough because the speed r

15、equired to escape completely from the earths gravity is seven miles per second, or over twenty-five thousand miles per hour.once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. a rocket aimed at the moon, for instance, will “coast”(滑行) the rest of the way because the

16、 earths gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. this “coasting” is known as “free fall”. that does not mean the rocket is falling down towards the earth but that it is traveling freely in space without the aid of power, like a bicycle coasting d

17、ownhill.free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all the time.as there is always the earths gravitational(地心引力的)pull, people （ ）. （ ）a.accept it without questioning itb.never notice its presencec.hardly think about how t

18、o use itd.often try to escape from it4、escaping from the earththe earth has a force that pulls things toward itself. we call this force gravity(地心引力). this is something we live with all the time, and we take it for granted and hardly ever think about it. but it is a most important factor in rocket o

19、peration and must be overcome if we are to get anywhere in space, or off the ground at all.take the throwing of a ball as an example. the harder the ball is thrown, the faster and higher it will go. what is the secret its speed. if we could throw the ball hard enough it would go up and up forever an

20、d never come down. the speed at which it would have to be thrown to do this is known as escape speed. of course, we cannot throw a ball hard enough because the speed required to escape completely from the earths gravity is seven miles per second, or over twenty-five thousand miles per hour.once esca

21、pe speed has been reached by a spacecraft(宇宙飞船), no further power is needed. a rocket aimed at the moon, for instance, will “coast”(滑行) the rest of the way because the earths gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. this “coasting” is known as “f

22、ree fall”. that does not mean the rocket is falling down towards the earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill.free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all

23、the time.when a bicycle “coasts” downhill, it （ ）. （ ）a.runs along the hillsideb.does not need any further powerc.runs freely to all directionsd.does not meet with air resistance5、escaping from the earththe earth has a force that pulls things toward itself. we call this force gravity(地心引力). this is

24、something we live with all the time, and we take it for granted and hardly ever think about it. but it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all.take the throwing of a ball as an example. the harder the ball is th

25、rown, the faster and higher it will go. what is the secret its speed. if we could throw the ball hard enough it would go up and up forever and never come down. the speed at which it would have to be thrown to do this is known as escape speed. of course, we cannot throw a ball hard enough because the speed required to escape completely from the earths gravity is seven miles per second, or over twenty-five thousand miles per hour.once escape speed has been reached by a spacecraft(宇宙飞船), no f