Section 1.2: Solving Physics Problems
One of the things I love about physics is the insistence on math. I remember a while back, a person posted to /physics asking for a book that’d teach him QM without any math. Unfortunately, I think a lot of people think this way. I think it’s a symptom of a more general problem – most people don’t connect math with logic. But, of course, math is just a very tall tower of logic, and if you want to see all of physics, you’re going to have to climb pretty high in the tower.
The book does a solid job of explaining how to solve physics problems as I understand it. They say: “Identify, Set Up, Execute, Evaluate. To me, the big trick with physics problems is that first step. Physics problems have the often tricky combination of logic puzzles and hard math. So, it’s important to know the pieces you’re working with (equations, facts) and the operations that are available (what’s logically legal according to the problem). I find I and others have the most trouble with physics problems when we attempt to dive in without taking stock of the available information.
Of course, they actually left out a few crucial steps. It should go: “Identify, Set Up, Execute, Fail, Frustration, Second Attempt, Anger, Go Home, Explain Problem to Friend, Find Solution is Obvious, Evaluate, Feel Stupid.”
The second part of section 1.2 deals with the physics idea of idealized models. As many of you know, idealized models are the butt of many jokes in physics, of the sort “Imagine a penis as a sphere constantly ejaculating in every direction, with an average flux of Φ.” Or, as my mechanics professor once said, “We physicists live in an ideal world.”
I don’t have anything new to say about idealizations, so I’ll refrain. I think we’re all aware of the benefits and pitfalls of idealized physics.
Wow, these first few sections are going pretty fast. I’ll remember this fondly when I’m knee deep in cross products…