宏观经济学课件(英文版)9.ppt

Chapter8CapitalUtilizationandandUnemployment1

CapitalInputWeextendthemicroeconomicfoundationstoallowforavariablecapitalutilizationrateand,hence,foravariablesupplyofcapitalservices.Thenweuseourmarket-clearingapproachtotherentalmarkettoassessthedeterminationofthequantityofcapitalservices.2

CapitalInputUptonow,wedidnotdistinguishthestockofcapital,K,fromthequantityofcapitalservicesusedinproduction.Inpractice,thecapitalutilizationratecanvary.3

CapitalInput4

CapitalInput5

TheDemandforCapitalServices6

TheDemandforCapitalServicesThemaximizationstillentailstheequationofthemarginalproduct,MPK,totherealrentalprice,R/P.7

TheDemandforCapitalServices8

TheDemandforCapitalServices9

TheSupplyofCapitalServicesOnthesupplyside,weassumedthatownersofcapital(households)suppliedalloftheircapital,K,totherentalmarket.However,ownersnowhaveachoiceaboutthecapitalutilizationrate,κ.Foragivenstockofcapital,K,ownerscansupplymoreorlesscapitalservicesperyearbyvaryingκ.10

TheSupplyofCapitalServicesThequestioniswhywouldanownereversetκbelowitsmaximumpossiblevalue?Thismaximumrate,correspondingtotheoperationofmachines24hoursperdayand7daysperweek,is8736hoursperyear.11

TheSupplyofCapitalServicesOnereasontosettheutilizationrate,κ,atlessthanitsmaximumvalueisthatincreasesinκtendtoraisethedepreciationrate,δ.Wecancapturetheseeffectsbywritingthedepreciationrateasanupward-slopingfunctionofκ:δ=δ(κ).12

TheSupplyofCapitalServicesOwnersofcapitalchoosetheutilizationrate,κ,tomaximizethenetrealincomefromsupplyingcapitalservices:netrealincomefromsupplyingcapitalservices=realrentalpayments-depreciation=(R/P)·κK–δ(κ)·K.13

TheSupplyofCapitalServicesIfwetakeoutsidethevariableK,wecanwritetheresultas:netrealincomefromsupplyin