EF 152 Spring, 2009 Lecture 6-11Module 6, Lecture 12ndLaw of ThermodynamicsNATURAL PROCESSES TEND TO MOVETOWARDSA STATE OF GREATER DISORDERIIEF 152 Spring, 2009 Lecture 6-12Laws of Thermodynamics1stLaw: Conservation of ________2ndLaw: Preferred __________ of a processSlide a book across a table, or drop a bowling ball onto the floor. Where does the lost mechanical energy go?Is it ever possible to reverse the process?A. YesB. NoIs it ever possible to convert heat back into mechanical energy?A. YesB. NoEF 152 Spring, 2009 Lecture 6-13Heat Engines Direct mechanical energy_______ power_______ powerMost energy comes from ______Burning ____________________ reactionsHeat is useful for ________________To operate a machine, we need ________________Need to convert ______ to _________________EF 152 Spring, 2009 Lecture 6-14Heat Engine: SchematicQW=1stLawThermal Efficiency, η=ηCombine equationshchcQQQQ−=+=11ηchQQQ+=Hot ThermalReservoir, ThCold Thermal Reservoir, TcEngineQhQcW
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