HOMEWORK#1PROBLEMSET
1.Asampleofmetalwithamassof212gisheatedto125.0°Candthendroppedinto375g
ofwaterat24.0°CIfthefinaltemperatureofthewateris34.2°C,whatisthespecificheatof
themetal?(Assumenoheatlossestothesurroundings.)
2.Findtheworkdoneonagasthatexpandsas
indicatedinthefigure.
3.Calculatethepowerperunitareaemittedfromthesun’ssurface,assumingthatthesun
isaperfectblackbodyradiator,withasurfacetemperatureof~5,800K.
4.AnidealgasinitiallyatPi,Vi,andTiistakenthroughacycleasshown.
(a.)Findthenetworkdoneonthegaspercycle.
(b.)Whatisthenetenergyaddedbyheattothesystempercycle?
(c.)Obtainanumericalvalueforthenetworkdonepercyclefor1.00molesofgasinitially
at0°C.
5.(a.)Howmanyjoulesofenergyareneededtochange10.0goficeat0.00°Ctowaterat
20.0°C?
(b.)Howmanykilojoulesofenergyareneededtochange20.0gofwaterat20.°Ctosteam
at100.°C?
1.
ORinothersunits831Joulesper(kg*K)
2.
Bothanswersareacceptableforfullcredit,witheithersign
3.P=Aε σT^4->P/A=ε σT^4=(1)(5.67e-8W/m2K4)(5800K)^4=6.42e+7W/m^2
4.
5.(a.)
(b.)