Sometimes it can be useful to be reminded about the ways in which the various 2nd law equations are interrelated. Here is an outline of my picture of the situation. Other versions of this are of course possible. I just wanted to get my own grip on the logic which links them. It’s worth remembering that the 2nd law is an observation (ie it’s not proved using axioms, despite the earnest hopes of certain physicists).
Patrick Andrews has a PhD in Mechanical Engineering from Heriot-Watt University and an MSc in Neuroscience from the University of Cambridge.
A former Chartered Engineer and Chartered Mathematician, Patrick has worked in management consultancies and high-tech startups, and in academia as a postdoc in Applied Mathematics at Cambridge and a maths lecturer at De Montfort University.
Patrick is the father of three delightful (but not uniformly mathematical!) daughters.