- #1
Master1022
- 611
- 117
- Homework Statement
- A block of metal (mass m, specific heat c) is originally at temperature T1. A reversible heat engine is run between the block and the surroundings at T0. Find an expression for the work extracted from the engine (considering both cases of T1 > T0 and T0 < T1)
- Relevant Equations
- 1st Law: Q - W = U
Hi,
I am quite confused about how to approach this problem. I have seen variations of this problem where there is a heat engine between two blocks, but in this case the surroundings are massless, so I don't believe that approach will work here.
Method:
I have first started with the case that [itex] T_1 > T_0 [/itex]. I have noted that [itex] Q - W = \Delta U [/itex].
I have first written down [itex] dU = mc dT_1 [/itex] and [itex] dQ = -mc dT_1 [/itex]. However, substituting those into the 1st law above and integrating, does not yield the correct answer.
Does anyone have any tips on where I should begin?
Thanks in advance
I am quite confused about how to approach this problem. I have seen variations of this problem where there is a heat engine between two blocks, but in this case the surroundings are massless, so I don't believe that approach will work here.
Method:
I have first started with the case that [itex] T_1 > T_0 [/itex]. I have noted that [itex] Q - W = \Delta U [/itex].
I have first written down [itex] dU = mc dT_1 [/itex] and [itex] dQ = -mc dT_1 [/itex]. However, substituting those into the 1st law above and integrating, does not yield the correct answer.
Does anyone have any tips on where I should begin?
Thanks in advance
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