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
Because we can feel that things are heavy, we think of weight as being a fixed quality of an object, but it is not really fixed
Because we can feel that things are heavy, we think of weight as being a fixed quality of an object, but it is not really fixed
admin
2015-05-21
49
问题
Because we can feel that things are heavy, we think of weight as being a fixed quality of an object, but it is not really fixed at all. If you could take a one-pound packet of butter 4, 000 miles out away 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 centre (in other words the radius(半径) of the earth is 4, 000 miles). When we took the butter 4, 000 miles out, it was 8, 000 miles from the centre, which is twice the distance.
If you double the distance between two objects, their gravitational attraction decreases four times weaker (two times two). If you treble(翻三倍)the distance, it gets nine times weaker (three times three). If you take it four times as far away, it gets sixteen times weaker (four times four) and so on.
选项
答案
解析
转载请注明原文地址:https://jikaoti.com/ti/NGwsFFFM
本试题收录于:
公共英语二级笔试题库公共英语(PETS)分类
0
公共英语二级笔试
公共英语(PETS)
相关试题推荐
Howdoesthewomanthinkofthenewteacher?
Whichisthebesttitle(题目)forthispassage?Inbigcitiespeoplecan______.
WhatisthewomandoinginBeijing?
Itispartly______thesummerdayislongerthateveryonecheersup.
Sept.10thWednesdayFineTodayisTeacher’sDay.Iattendedacelebration【M1】______meetingholdbyourschool.A
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirworktheymustreadletters,reports,tradepublication
Thelakelaybeforeme,blueandpeaceful,intheevening【36】.Oneithersidethemountainsrosesharplysurroundingitinakin
It’smyfirstwritinginthenewclass.IafraidImay76.______makelotsofmistake.Butwithoutpractice,Icannever
Americansareofteninahurry.Theyrushtowork,rushhome,andrushthroughtheirmeals.Workersandstudentsusuallyhaveon
随机试题
根据现行估值原则,对于交易所公开增发但未上市的新股,应采用的估值方法是()。
男性,74岁,体重60kg,全胃切除术后5天,大量肠液自腹腔引流管引出,左上腹疼痛。查体:左上腹轻压痛,无肌紧张。该病人热量每天基本需要量是
简述心力衰竭治疗中“减轻心脏负荷”的具体措施。
A.8~9个月B.24个月C.6~7个月D.15个月E.3~4个月出现捏、敲等探索性动作
根据《建设工程质量管理条例》的规定,在正常使用条件下,建设工程电气管线、给水排水管道、设备安装工程的最低保修期间为()。
1964年()提出了“随机漫步理论”,他认为股票价格的变化类似于化学中的分子“布朗运动”(悬浮在液体或气体中的微粒所做的永不休止的、无秩序的运动),具有“随机漫步”的特点。
供应链的不确定性主要表现在( )。
《弥渡山歌》歌曲的旋律婉转、飘逸,富有________的独特风格。
一个民族必须具有民族的自信心、自尊心和民族的凝聚力,这个民族才能够自立于世界。如果丧失了这些,这个民族就没有了希望,而民族的自尊心、自信心和民族的凝聚力又是基于对文化的优秀传统有所认识和了解才开始萌生的。所以()
结合材料回答问题:1994年1月2日,余祥林的妻子张在玉因患精神病走失失踪,张的家人怀疑张在玉被丈夫杀害。同年4月28日,余祥林因涉嫌杀人被批捕,后被原荆州地区中级人民法院一审被判处死刑,剥夺政治权利终身。后因行政区划变更,余祥林一案移送京山县公安局,经
最新回复
(
0
)