According to AAMC numbers, three passages worth of questions on the Ph/Ch section of your real MCAT would be typical. Feedback at SDN has not disagreed with this, so assume a good FL should have three physics passages. But the thing that seems to catch people off guard is when they mix topics. For instance, a passage on electrophoresis that focuses on F = qE and gel viscosity could very well be a physics passage in the test writer's eyes, but a biochemistry passage to a test taker.
So on that note, you should not blow off any physics topics while simultaneously paying extra attention to any topics that couple well with either biochemistry or anatomy. Fluids is a perfect example where the circulation of blood is often described by Pouisielle's law. Tidal volume ties in perfectly with the ideal gas law. Electric circuits ties together well with nerve conductivity, Muscle-skeletal examples are perfect for forces and torque. There are literally at least a hundred examples like these. These are all high-yield for the MCAT.
The other type of passage you should expect is based on an experiment. Analyzing data and understanding experimental logic is an important topic. This can tie with anything and everything in physics. The usual suspects in physics haven't really changed in terms of the new MCAT (fluids, waves, charged species, and forces), but the style of passages has changed a little and will continue to evolve until they have the exam they want.
So rather than worry about the topics, it is better to focus on the passage type and the questions that can be expected. Knowing your material cold can get you a good score, but a great score only comes from knowing how to interpret and answer their questions (in a timely fashion).
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