I don't know what level of physics you're taking, but the lecture portion is mostly motivational introduction (literally motivating particular types of solution

I don't know what level of physics you're taking, but the lecture portion is mostly motivational introduction (literally motivating particular types of solutions or insights), but it's not where you learn the details of models or techniques for solution. That is done in some combination of reading the text (before class), previous or concurrent math classes (algebra, calculus, analysis, linear algebra, ODE, complex analysis, PDE, abstract algebra each go really well with particular topics), recitation with a TA (where you can ask for aditional detailed questions), and homework sets (that you'll want to discuss with the TA as well). If you have good labs, you'll actually prove many of the relationships by experiment... and you'll see how hard it is to actually do science (there are so damn many ways to do physical things wrong!). Like programming the details involve sitting down and cranking out the solutions and having the aha moments by yourself. It's easy to be wowed by a lecture, but if you can't teach it to someone else you don't really understand it.