forces and motion - clancy school district 1：力与运动-克兰西学区

《forces and motion - clancy school district 1：力与运动-克兰西学区》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。

1、ForcesandMotionChapter10GravityüWhatisgravity?üGravityisaforcethatattractsobjectstogetherüOnearththisforceattractseverythingtoEarthüGravityisapullthateveryobjectexertsoneveryotherobjectüThestrengthofgravityüTheEarthisaverylargeobjectanditisalsoveryheavyüThismeansthatithasgotastron

2、ggravitationalfieldüThemoonissmallerthantheEarthandisnotasheavyandthereforehasasmallergravitationalfieldüThemoon'sgravityisonly1/6thasstrongastheEarth'sYouHaveGravityüEveryoneandeverythinghasitsowngravityüAllmasses,regardlessofsize,attractothermasseswithgravityüYoudon'tnoticethefo

3、rcefromnearbyobjectsbecausetheirmassissosmallcomparedtothemassoftheEarthTheMoreMatter…theMoreGravityüThemassofanobjectistheamountofmaterialtheobjectismadeofüThemorematerialtheobjectismadeof,themoremassithasüThingsthathaveabigmassarehardertomoveandhardertostopthanobjectswithjustali

4、ttlebitofmassMeasuringGravityüWeoftenaskhowmuchdoweweigh?üWeanswerinkilograms…..ThisisnotrightüOurmassisinkilogramsbutourweightisrelatedtothestrengthofgravityüTheweightofanobjectistheforceoftheearth'spullofgravityontheobjectüEverytimeyouweighyourselfonascale,youaremeasuringthepull

5、ofEarth’sgravityüWeshouldreallysaythatourweightisinNewtonsüForceismeasuredinnewtonsüAnewtonistheweightofacubeofbutterüThisisreallyimportantbecauseifwewenttothemoonourmasswouldNOTchangebutourweightwould.üMassdoesnotchangefromplacetoplaceüYourmassisthesameonboththeearthandthemoonbut

6、yourweightisdifferent.Youwouldappearlighteronthemoon.üMassismeasuredwithabalance,whereasweightismeasuredwithascaleComparisonsüThemoon’sgravityis1/6thatoftheearth’sgravityüThegravityofMarsis1/3thatoftheearth’sgravityüThemassofJupiteris2.5morethantheEarth’sgravityGravityTreatsEveryt

7、hingtheSameüNewtonsaidthegravityactsoneverything,largeorsmall,inthesamewayüTherateatwhichanobjectfallsDOESNOTDEPENDONITSMASS!!!!!üHeavyobjectsfallnomorequicklythanlightobjectsüTheaccelerationduetotheEarth'sgravityisthesameforallobjectsüAllfallingobjectsneartheearthaccelerateatther

8、ateofabout10m/spersecondüobjectsd