815.1 why do some things happen, while others do not? Lead shot Lead Thermal reservoir Control knob (a) Initial state i b) Final state 815.1 why do some things happen, while others do not? @friction, quasi-static V1→V O,=W,+W=nRTIn-+w >0) 2,=Wi+W,=nRTIn -I+w (<0) result 21+o2=2w>0 reversible3 §15.1 why do some things happen, while others do not? 2friction, quasi-static V1 →V2 Q1 = W1 +W f W f V V = nRT + 1 2 ln (>0) (>0) V2 →V1 Q W +W f = ′ 2 1 W f V V = nRT + 2 1 ln (< 0) (>0) result Q1 + Q2 = 2Wf > 0 Irreversible! ： §15.1 why do some things happen, while others do not?