帮我改下我的英文作文,
SeatbeltsarethemainsafetymeasureincarswhichareinstalledduetoNewton’sfirstLaws.Forexample,acarsuddenlystoptheoccupantsofthecarwillcontinuetomoveatthesamespeedandinthesamedirectionthatthecarwasmovingunlessacteduponbyanexternalforcebringingpassengerstorestinaccordancetoNewton'sfirstlaw.TheseatbeltactsasanexternalforcebringingdrivertorestinaccordancetoNewton'sfirstlaw.Ifthedriverisnotwearingtheseatbelt,theywouldeasilytocollidetotheglassport,orflyoutofthecar,thisasaconsequencesufferlifeinjuriesorevendeath.Useanequationtoshowisthat:A=V-Vo/twhereVisthefinalvelocityofthecarandVoistheinitialspeedofthedriverwhichinthiscaseisthespeedofthecarbeforebraking.InaccordancetoNewton’slaw,aforceisreducedsowilltheforceactingonthepersonasF=ma.
Airbagisanimportantsafety,everytimeyoudriveryourcar,youarebeingprotectedbyanairbags.FromtheNewton'sfirstlawactingasanexternalforceandbringingapersontorestandthatpersonisstilltravellingatthesamespeedandinthesamedirectionthatthecarwastravelling.Themomentthesensorfortheairbagdetectsasuddendeceleration,anelectricalsparkignitesthecompoundsodiumazideinsidethebagproducingnitrogengasandthebaginflates.
Theairbagisdesignedtopreventimportantinjurytotheoccupant’sheadandchestandassoonasitisstruckitbeginstoinflateatasteadyratethuspreventinganybouncingandseriousinjuryduetoimpactwithit.Thishastheeffectofbringingthepersontorestoveranextendedperiodoftimethereforereducingtheamountofaccelerationexperienced.InaccordancetoNewton’ssecondlaw,asaccelerationisreducedsoistheamountofforceactingontheperson.