A completely reversible heat pump produces heat at a rate of 300 kW to warm a house maintained at 248C. The exterior air, which is at 78C, serves as the source. Calculate the rate of entropy change of the two reservoirs and determine if this heat pump satisfies the second law according to the increase of entropy principle.

Energy Kinetic Energy - energy of motion Potential Energy - stored energy Linear Kinetic Gravitational Potential Q: What about the spring potential Spring Potential Lagrange's Equations/Method (Sec. 1.5) * Energy-based method * Allows us to ignore internal/interaction forces (if we want to) * Usually based around: - generalized coordinates - virtual displacements Generalized Coordinates Lagrange's Equation (with no external forces or damping) Simple Linear Example of Lagrange's Method Simple Rotational Example of Lagrange's Method A Less-Simple Example (Newton/Euler) A Less-Simple Example (Lagrange) Lagrange's Met