牛顿运动定律与体育运动(素材多)

HowdoesNewton'sThreeLawsofMotionsapplyto

sports?WhatareNewton’sThreeLawofMotion?

Newton’s1stLawofMotion

Anobjectatrestwillstayatrest,unlessanoutsideforceisplacedonit.CommonlyknownasInertiaHowdoesNewton’s1stLawapplytosports?

Sportexamples:Statics–athlete/objectismotionlessOlympiclifterDiverbeforeadiveGymnastafterthelandingDynamics–athlete/objectisinmotion.CyclistcoastingataconstantvelocitySkiercoastingataconstantvelocityNewton’s2ndLawofMotion

IsthemostcomplicatedofthelawsTheaccelerationofanobjectasproducedbyanetforceisdirectlyproportionaltothemagnitudeofthenetforce,inthesamedirectionasthenetforce,andinverselyproportionaltothemassoftheobject.Thechangeofmotionofanobjectisproportionaltotheforceimpressed;andismadeinthedirectionofthestraightlineinwhichtheforceisimpressed.Newton’s2ndLawofMotioncont.

FormulaF=maF=Force(1N) 1lb=4.5Nm=mass(kg)1kg=2.2lbsWeight=massxaccelerationofgravityW=mgW=1kgx(9.8m/s2)=9.8Na=accelerationofgravity9.8m/s2or32.2ft/s2Newton’s2ndLawofMotioncont.

WhatisaForce?AvectordefinedbythesizeanddirectionA→totheright(+)ora←left(-).Thelength=theforce.Thelongerthelinethegreatertheforce,andviceversaonshorterThesamefortheUp↑(+)andthedown↓(-)arrow.

Therearedifferenttypesofforce:TensileForce(Pullingarope)

CompressiveForce(Pushingtogether)

Noncontactforces–Gravity,magneticforces,electricityNewton’s2ndLawofMotioncont.

NetForce=thesumofallexternalforcesactingonanobject.

F=F1+F2+F3+…..Statics–Bodiesatrestequalzero

F=0Collinearforces–inthesameline,maybeinthesameoroppositedirectionandmaybeaddedtodetermineresultantforce.Example:Tug–of–WarTeam1has3membersexertingthefollowingforces:100N,200N,400Nandteam2has3membersexertingthefollowingforces:200N,300N,500N;whowillwin?Team1 Team2(-100N+-200N+-400N)+(200N+300N+500N) (-700N)+(1000N)=300N Team2isthewinnerdueto300Nmoreforce.Newton’s2ndLawofMotionExampleClicktheboxbelowtoviewexampleHowdoesNewton’s2ndLawapplytosports?PitchingabaseballHowfastistheballmoving?WeightliftingHowmuchforcedoIneedtoliftthisweight?TrackandFieldHowfastisthatpersonrunning?Howmuchforceisneededtothrowtheshot-put50feet?

Newton’s3rdLawofMotionForeveryaction,thereisanequalandoppositereaction.ActionequalsReactionHowdoesNewton’s3rdLawapplyt