At the end of this section, you should be able to:

1.  Articulate the idea of the 2nd law of thermodynamics 

2. Explain what a “heat engine,” “heat pump”, and “refrigerator” are in a thermodynamics context 

3. Conceptually, calculate efficiencies for heat engines and heat pumps

4. Calculate the work output from an ideal heat engine

5. Calculate the work input for an ideal heat pump, refrigerator, or AC