Example #3 on 1st law Known:Data are provided for air contained in a vertical piston- cylinder fitted with an electrical resistor.Neglect friction. Find:heat transfer from the resistor to the air for (a)air alone;(b)air piston. Schematic and Given Data: -Piston Piston Patm=1 bar System System mpiston =45 kg boundary boundary Apiston=.09 m2 for part (b) for part (a) g=9.81m/s2. Air Air slowly Good mair=.27 kg V2-V1=.045m3 insulator △lair=42kJ/kg. (a)air alone (b)air piston 上游充通大 March 9,2018 8 SHANGHAI JIAO TONG UNIVERSITYMarch 9, 2018 8 Example #3 on 1st law Known: Data are provided for air contained in a vertical piston– cylinder fitted with an electrical resistor. Neglect friction. Find: heat transfer from the resistor to the air for (a) air alone; (b) air + piston. Schematic and Given Data: slowly Good insulator g =9.81 m/s2 . air alone air + piston