首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Weight on and off the Earth We are so used to our life on the surface of the earth that it can be quite an effort for our mi
Weight on and off the Earth We are so used to our life on the surface of the earth that it can be quite an effort for our mi
admin
2014-09-13
64
问题
Weight on and off the Earth
We are so used to our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted. Because we can feel that things are heavy, we think of "weight" as being a fixed quality in an object, but it is not really fixed at all. If you could take a one-pound packet of butter 4, 000 miles out from the earth, it would weigh only a quarter of a pound.
Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4, 000 miles out into space? The reason is this; all objects have a natural attraction for all other objects; this is called gravitational attraction. But this power of attraction between two objects gets weaker as they get farther apart. When the butter was at the surface of the earth, it was 4, 000 miles from the center. When we took the butter 4, 000 miles out, it was 8, 000 miles from the center, which is twice the distance. If you double the distance between two objects, their gravitational attraction decreases two times two. If you treble the distance, it gets nine times weaker(three times three)and so on.
So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth.
What about the weight of our pound of butter on the surface of the moon? At the distance the pull of the earth is about 4, 000 times smaller than it is here on the surface, so we can forget all about the earth-pull on our butter.
On the other hand, on the moon there will be an attraction between the butter and the moon, but the butter will weigh only about one-sixth as much as it does on the earth. This is because the moon is so much smaller than the earth. The amount of gravitational pull that a body produces depends on the amount of material in it. A packet of butter has a gravitational pull of its own; but this is very small in relation to the pull of something as large as the moon, or the earth, or the sun.
The main idea of this passage is______.
选项
A、different weight systems in different places
B、freedom from traditional ideas
C、traveling from the earth to the moon
D、the effect of gravitation on weight
答案
D
解析
本篇文章通篇讲的是重量是由引力产生的,并进一步阐述了物体问引力的变化、物体本身的重量,以及物体间的距离这三者之间的关系,主要讲的还是引力对重量的作用。
转载请注明原文地址:https://kaotiyun.com/show/0HQd777K
本试题收录于:
职称英语理工类C级题库职称英语分类
0
职称英语理工类C级
职称英语
相关试题推荐
Itisoutrageousthatthesebuildingsremainemptywhilethousandsofpeoplehavenohomes.
Americansstillhavebeengainingweight,althoughtheyhavecuttheiraveragefatintakefrom36to34percentoftheirtotald
Thousandsofpeopleperishedinthestorm.
LightNight,DarkStarsThousandsofpeoplearoundtheglobestepoutsidetogazeattheirnightsky.Onaclearnight,with
LightNight,DarkStarsThousandsofpeoplearoundtheglobestepoutsidetogazeattheirnightsky.Onaclearnight,with
DangersAwaitBabieswithAltitudeWomenwholiveintheworld’shighestcommunitiestendtogivebirthtounderweightbabie
DangersAwaitBabieswithAltitudeWomenwholiveintheworld’shighestcommunitiestendtogivebirthtounderweightbabie
Thousandsofpeopleperishedinthestorm.
SaunaCeremonial(仪式性的)bathinghasexistedforthousandsofyearsandhasmanyforms,oneofwhichisthesauna.TheFinnsha
随机试题
袁枚在诗歌创作上主张【】
对作案多起的刑事案犯,所采用的手段、作案的具体情节、造成的后果基本相同,而案犯又供认不讳、各方均无异议的案件,一般采用的文书行文章法是
患儿,10个月。腹泻3天,鼻塞流涕,每日大便10余次,呈稀水样,臭味不甚,尿黄。查体:体温38℃,皮肤弹性尚好,前囟平,哭时有泪。听诊心肺正常,肠鸣音亢进,舌苔薄白,指纹红,达于风关。大便镜检无异常。应首先考虑的是
A.灰黄霉素B.两性霉素BC.制霉菌素D.克霉唑E.酮康唑外用无效,口服治疗体表癣病的药物是
背景某安装公司承包一水处理厂的设备安装工程,安装公司负责设备的采购、施工(PC合同),合同工期为365天(2013年1月1日~2013年12月31日)。合同签订后,因建设单位在征地环节上出了问题,施工场地延后3个月才交付给安装公司,所以建设单位将
对外贸易系数
下列关于公司首次公开发行新股,说法正确的有()。
【2015工商银行】第一个事实:电视广告的效果越来越差,一项跟踪调查显示,在电视广告所推出的各种商品中,观众能够记住其品牌名称的商品的百分比逐年降低。第二个事实:在一段连续插播的电视广告中,观众印象较深的是第一个和最后一个,而中间播出的广告留给观众的印象
VBA中运算符“&”的含义是()。
HowlongdidEmilyDickinsonliveinthehousewhereshewasborn?
最新回复
(
0
)