How beneficial will AP Physics C be for freshmen year college physics?

The advice to not attempt to place out of college intro physics is good--my experience is that the instruction in intro college classes is better than in the equivalent AP class. I would say that whether to take AP Physics C specifically depends somewhat on what you would take instead. AP Physics would certainly look good on your college applications, although there may be other options. Although some of the material would be duplicated, I am inclined to recommend taking AP Physics, unless there's a compelling alternative AP class.

Back when I was in High School (in the late 80's) things were a bit different with AP classes. We did not have an AP Physics C Mechanics. We had AP Physics, that's it, one course. We did have AP Calc AB and AP Calc BC.

I took AP Physics and AP Calc AB in High School and did not place out in college (3 out of 5 on the AP exam on both - a 4 or 5 was required to place out) and I also took Honors Chem in High School.

While I did not place out, having those courses under my belt helped immensely in college. We covered just about 100% of the Freshman Physics material, about %90 of the freshman Calc, and 80% of freshman chem. The courses in my freshman year were more like review courses. That gave me both a better understanding of the matieral, and a bit of a cushion in my classes to get used to college.

I found it very useful because I was able to develop a very good foundation in the courses that just about everything else in my major built off of (Physics and Calc) and it also made Chem a lot easier (Every freshman engineer took Chem, but for most Civil engineers, there was very little chemistry after freshman year) It also made those classes a lot easier. Those also tended to be (at least for me) the classes that were the hardest to get help in (large 200+ student lectures, the professors don't know you, and the TA's that teach the recitation sections are often dissinterested because it is a basic level class). Haven taken them already in HS helped a lot.

-dave

AP Physics C: Mechanics is a calculus-based physics course that covers kinematics, dynamics, energy, momentum, rotation, gravitation and oscillation. This course is the first of a two-course sequence that is equivalent to the introductory physics sequence taken by science and engineering students at most colleges and universities.

AP Physics C: Electricity and Magnetism builds on the C: Mechanics with the addition of forces exerted on charged particles, electric and magnetic fields, electric circuits and their components, and the nature of electromagnetic radiation. This course is equivalent to the second semester of the introductory physics sequence typically offered at colleges and universities. This course applies both differential and integral calculus.

The majority of schools offer Physics C Mechanics as a two-semester course to students whose prior physics experience is usually a basic high school physics class. Some schools offer Physics C Mechanics as a one-semester course, and usually do so in combination with a second semester of Physics C Electricity and Magnetism; in this case the students have usually been successful in a previous challenging physics course, such as AP Physics B. Most students who take Physics C Mechanics are high school seniors.

A textbook, of course, is essential. However, the teacher should be the primary source of understanding, and the textbook secondary. The chosen texts are usually the same as those chosen for corresponding college calculus-based physics courses, and are the source of most homework questions. A well-chosen AP physics review book purchased at the start of the course can also be very useful for the student.

Planning is crucial. A well-organized course with a well timed logical progression of ideas is often difficult for a new AP Physics C teacher to create. The task will be easier and more successful if one can get the help of an experienced AP Physics teacher who understands the special needs of your school and situation.