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
93
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.
We do not feel the gravitational pull of a packet of butter because______
选项
A、it is too small to have a gravitational pull of its own
B、its pull is so small that we tend to ignore it
C、its pull disappears in the presence of the earth’ s gravitation
D、it tends to melt and loses its gravitational pull
答案
B
解析
最后一段第三句说明一个物体产生的引力与物体本身的重量有关。最后一段第四句又表明由于本身重量较小,一包黄油产牛的引力很有限,相对于月球、地球、太阳等产生的强劲引力来说,比较容易被我们忽略。
转载请注明原文地址:https://kaotiyun.com/show/cHQd777K
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
Americansstillhavebeengainingweight,althoughtheyhavecuttheiraveragefatintakefrom36to34percentoftheirtotald
LightNight,DarkStarsThousandsofpeoplearoundtheglobestepoutsidetogazeattheirnightsky.Onaclearnight,with
LightNight,DarkStarsThousandsofpeoplearoundtheglobestepoutsidetogazeattheirnightsky.Onaclearnight,with
DangersAwaitBabieswithAltitudeWomenwholiveintheworld’shighestcommunitiestendtogivebirthtounderweightbabie
AinyourbodyBwithoutwaterCbeforelongDforachangeEonabusydayFtoyourweightDehydrationmayoccurifthereis
SheworeagorgeousVictoriangownwhichwassaidtobeworththousandsofdollars.
Thousandsofpeopleperishedinthestorm.
Thousandsofpeopleperishedinthestorm.
随机试题
中国共产党的宗旨是由
便携式网络图像格式文件的扩展名是______。
在Excel中,B3:F6表示引用了__________个单元格。
根管的数目与牙根的数目之间的关系如何
根据《医疗机构管理条例》的规定,下列说法中错误的是
章先生,32岁,因车祸致脾破裂,急诊入院。病人胸闷、气促、出冷汗、脉细速,BP68/50mmHg,其体位应为
国家无偿收回划拨土地使用权的原因有()。
方先生将一笔10万元的资金投资在一个年收益率为6%的工程项目中,试估算,大约经过()年,这笔资金的本利和可以达到20万元。
根据以下资料,回答问题。2012年第三季度全国100个城市的公共就业服务机构市场中,用人单位通过公共就业服务机构招聘各类人员约643.3万人,进入市场的求职者约610万人,岗位空缺与求职人数比率比上年同期上升了l%。上年同期这100个城市中,用人单位
若查找每个记录的概率均等,则在具有n个记录的连续顺序文件中采用顺序查找法查找一个记录,其平均查找长度ASL为()。
最新回复
(
0
)