Chapter1ParticleKinematicsI)Chooseonecorrectansweramongfollowingchoices1.Anobjectismovingalongthex-axiswithpositionasafunctionoftimegivenbyx=x(t).PointOisatx=0.TheobjectisdefinitelymovingtowardOwhenA.B.C.D.2.Anobjectstartsfromrestatx=0whent=0.Theobjectmovesinthexdirectionwithpositivevelocityaftert=0.TheinstantaneousvelocityandaveragevelocityarerelatedbyA.B.C.D.canbelargerthan,smallerthan,orequalto3.Anobjectismovinginthexdirectionwithvelocity,andisnonzeroconstant.Withwhent=0,thenfort>0thequantityisA.Negative.B.Zero.C.Positive.D.Notdeterminedfromtheinformationgiven.4.Anobjectismovingonthexy-planewithpositionasafunctionoftimegivenbyr=at2i+bt2j(aandbareconstant).Whichiscorrect?A.Theobjectismovingalongastraightlinewithconstantspeed.B.Theobjectismovingalongastraightlinewithvariablespeed.C.Theobjectismovingalongacurvedpathwithconstantspeed.D.Theobjectismovingalongacurvedpathwithvariablespeed.5.Anobjectisthrownintotheairwithaninitialvelocitym/s.Ignoretheairresistance(空气阻力).Atthehighestpointthemagnitudeofthevelocityis()(A)0(B)4.9m/s(C)9.8m/s(D)m/s6.Twobodiesarefallingwithnegligibleairresistance,sidebyside,aboveahorizontalplane.Ifoneofthebodiesisgivenanadditionalhorizontalaccelerationduringitsdescent,itA.strikestheplaneatthesametimeastheotherbody.B.strikestheplaneearlierthantheotherbody.C.hastheverticalcomponentofitsvelocityaltered.D.hastheverticalcomponentofitsaccelerationaltered.7.Atoyracingcarmoveswithconstantspeedaroundthecircleshownbelow.0v?vxyWhenitisatpointAitscoordinatesarex=0,y=3manditsvelocityis6m/s.WhenitisatpointBitsvelocityandaccelerationare:A.-6m/sand12m/s2,respectively.B.6m/sand-12m/s2,respectively.C.6m/sand12m/s2,respectively.D.6m/sand2m/s2,respectively.8.Astoneistiedtoa0.50-mstringandwhirledataconstantspeedof4.0m/sinaverticalcircle.Itsaccelerationatthebottomofthecircleis:A.9.8m/s2,upB.9.8m/s2,downC.8.0m/s2,upD.32m/s2,up9.Aboatisabletomovethroughstillwaterat20m/s.Itmakesaroundtriptoatown3.0kmupstream.Iftheriverflowsat5m/s,thetimerequiredforthisroundtripis:A.120sB.150sC.200sD.320sII)Fillintheemptyspacewithcorrectanswer1.Aparticlegoesfromx=-2m,y=3m,z=1mtox=3m,y=-1m,z=4m.Itsdisplacementis:.2.Thex-componentofthepositionvectorofaparticleisshowninthegraphinFigureasafunctionoftime.(a)Thevelocitycomponentvxattheinstant3.0sis.(b)Whenisthevelocitycomponentzero?Thetimeis.(c)Istheparticlealwaysmovinginthesamedirectionalongthex-axis?.3.Theangleturnedthroughbyawheelisgivenbyθ＝at+bt2,whereaandbareconstants.Itsangularvelocityω＝,anditsangularaccelerationβ＝.4.Whenaradiowaveimpingesontheantennaofyourcar,electronsintheantennamovebackandforthalongtheantennawithavelocitycomponentvxasshownschematicallyinFigure.Roughlysketchthesamegraphandindicatethetimeinstantswhen(a)Thevelocitycomponentvxiszero;(b)Theaccelerationcomponentaxiszero;(c)Theaccelerationhasitsmaximummagnitude.5.Acaristravelingaroundabanked,circularcurveofradius150monatesttrack.Attheinstantwhent=0s,thecarismovingnorth,anditsspeedis30.0m/sbutdecreasinguniformly,sothatafter5.0sitsangularspeedwillbe3/4thatitwaswhent=0s.Theangularspeedofthecarwhent=0sis,theangularspeed5.0slateris,themagnitudeofthecentripetalaccelerationofthecarwhent=0sis,themagnitudeofthecentripetalaccelerationofthecarwhent=5.00sis,themagnitudeoftheangularaccelerationis,themagnitudeofthetangentialaccelerationis.6.Aprojectileislaunchedatspeedv0atanan...
