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Question 1

Cylinder contains O2 (heat capacity 21.10J/(mol.K) at pressure of 2.00atm. Vol = 4.00L, T=300K. Assume ideal gas. Given these 4 processes: (1) Heated at cnst pressure from initial state (state 1) to state 2, which has T=450K. (2) Cooled at cnst vol to 250K (state 3). (3) Compressed at constant temp to vol of 4.00L, (4) Heated at constant volume to 300K (back to state 1).

Solve: (a) Show these 4 processes in p-V diagram, giving numerical val of p and V in each of 4 states. (b) Calculate Q and W for each process. (c) Calculate net work. (d) What is the efficiency? How does the efficiency compare to carnot engine operating between same min and max temp of 250K and 450K?


Question 2

Given black bear (assume as sphere 1.5m diameter), bear has 2 layers of insulation: 1 layer of fat 4.0cm thick, thermal conductivity of fat = 0.20 W / (m.K), surrounded by layer of air trapped inside fur. The outer surface layer of the fur is 2.7C during hibernation, while inner surface is 31.0C. What is temp at fat-inner fur boundary, and how thick should the air layer contained within fur be so that the bear loses heat at rate = 50.0W