Chapter20ThespecialtheoryofrelativityAlbertEinstein(1879~1955)20-1TroubleswithclassicalphysicsThekinematicsdevelopedbyGalileoandthemechanicsdevelopedbyNewton,whichformthebasisofwhatwecall“classicalphysics”,hadmanytriumphs.However,anumberofexperimentalphenomenacannotbeunderstoodwiththeseotherwisesuccessfulclassicaltheories.1.TroubleswithourideasabouttimeThepions(or)createdatrestareobserved+−todecay(tootherparticles)withanaveragelifetimeofonly.Inoneparticularexperiment,pionswerecreatedinmotionataspeedof.Inthiscasetheywereobservedtotravelinthelaboratoryanaveragedistanceofbeforedecaying,fromwhichweconcludethattheydecayinatimegivenby,muchlargerthantheli...
