测绘工程专业英语课文翻译Unit-16Gravity Measurment

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1、Unit16GravityMeasurment(重力测量)Asknownfromdailyexperience,themostconspicuousforcepresentonthesurfaceoftheEarthisgravity.GravityistheforcethatpullsthingstowardsthecenteroftheEarth.Gravityaffectsalmosteverythinginourlives.Fromclockstohydroelectricdams,fromthetidesoftheoceanstoplantlife,gravityplaysanim

2、portantrole.GravitygovernsourheightandshapeandkeepsusfromfallingoffthesurfaceoftheEarth.(从日常经验中得知，地球表面最显著的引力是重力。地心引力是把东西拉向地球中心的引力我们生命中的一切。从时钟到水电站，从海洋的潮汐到植物的生命，重力起着重要的作用。重力支配着我们的高度和形状，使我们保持活力会关闭地球的表面。)ConceptsofGravity(重力的概念）Gravitationistheforcethatpullsorattractsallbodiesintheuniversetowardsoneano

3、ther.Thefamouslawofuniversalgravitation,firstformulatedmathematicallybyNewtonstatesthefactthatanytwophysicalbodiesattracteachother.Thisgravitationforce,whichisproportionaltotheproductofthetwomasses(Mandm)andinverselyproportionaltothesquareoftheirdistance,canbeexpressedasfollows:（万有引力是吸引或吸引宇宙中所有物体的力

4、量，万有引力定律，由牛顿在数学上首次表述为任何两个身体互相吸引。这种引力，这是成正比的产品的m米驴（M和M），并成反比的平方距离，可以表述如下：）inwhichGisknownasNewton’sgravitationalconstant.SincetheEarthisspinning,anyobjectwithinorontheEarth’ssurfacepursuesacircularpathastheEarthrotatesonitsaxis.IfthebodyisontheEarth’ssurface,itfollowsthecircularpathbecauseitisheldon

5、totheEarth’ssurfacebythegravitationalforce.However,thebodyasitpursuesacircularpathexertsanoutwardforcecalledthecentrifugalforce.Thesumofthegravitationandthecentrifugalforceiscalledthegravityforce.Thegravityforceisstrongeronthepolesthanontheequator,sincethecentrifugalforcevanishesonthepolewhereasthe

6、valueofthecentrifugalforceontheequatorisobtainedbiggest.Eventhoughcentrifugalforceisthestrongestontheequator,itisabout0.35%ofthegravitationforce.Thereforethegravityismainlygovernedbythegravitationforce.Thegravitycausesanobjecttohaveweightand,iftheobjectisfreetomove,tofallwithincreasingspeed(i.e.,th

7、ebodyaccelerates)towardthecenteroftheEarth.TheaccelerationexperiencedbythatobjectasitmovestowardtheEarth’scenteriscalledtheaccelerationofgravity,whichisthequantityobservedwhengravitymeasurementsaremade.（其中G