Ch.13EnergyIII:ConservationofenergyCh.13EnergyIII:ConservationofenergyCh.13EnergyIII:ConservationofenergyInthischapter:weconsidersystemsofparticlesforwhichtheenergycanbechangedbytheworkdonebyexternalforces(系统外的力)andnonconservativeforces.ffiiUKUK+=+Lawofconservationofmechanicalenergy:“Inasysteminwhichonlyconservativeforcesdowork,thetotalmechanicalenergyremainsconstant”Ch.13EnergyIII:Conservationofenergy13-1WorkdoneonasystembyexternalforcesPositiveexternalworkdonebytheenvironmentonthesystemcarriesenergyintothesystem,therebyincreasingitstotalenergy;viceversa.Theexternalworkrepresentsatransferofenergybetweenthesystemandtheenvironment.extsyssysWUK=+...
