I agree with the point that freshman may not be at a level in math to perform the abstract or more advanced math computations that are found in Algebra which means their ability to do so in a physics course would be very limited at best. I think that the premise behind physics first is teach the conceptual concepts found in a physics curriculum to help students better understand biology and chemistry. This is to say that a physics course then taken when students are in their junior and senior year of high school will have the more advanced math skills and they will have taken additional math such as a second year of algebra, trig, and/ or calculus. From here the more abstract topics in physics can then be presented.
Physics first should be matched to the ability of the students taking this course and is used to provide the intellectual foundation for biology and chemistry. In addition, algebra skills can be learned and better understood through the topics of physics provided they are at a level that matches or is a step above the freshman.
It has always been my understanding the Physics First curriculum is meant as an introduction and a foundation to topics that are physics based found in biology and chemistry.......