Understand Physics First, Then AP Physics C
Be sure you understand physics before preparing specifically for the AP Physics C exams.
I’ve taught Physics C with great success for many years. But, not just anyone can sign up for my
Physics C class. I only take students who have completed Physics 1, and for good reason. The C course is
very deep. It requires that you have not just an idea about, but a true mastery of, Physics 1- and 2-level
material.
Now, your first physics course might not have formally been labeled “Advanced Placement.” Any
rigorous introductory class is sufficient preparation for Physics C. Nevertheless, before you even begin to
discuss a calculus-based approach to problem-solving, you MUST have a solid conceptual understanding
of physics at the introductory level.
My advice to my Physics C students has always been to know the basics. An average difficulty
Physics C question is equivalent to an above-average (and more calculational) Physics 1 or 2 question.
Someone who knows physics cold at the 1/2 level could do reasonably well on the Physics C exam.
Therefore, you start your preparation by answering the following with brutal honesty: “Could I solve
any Physics 1 level mechanics, or Physics 2 E&M, problem? Would I recognize the appropriate
equations, relationships, and definitions instantly, without wrinkling my forehead for more than a few
seconds?”
If the answer is “no,” then the most efficient way to improve your Physics C performance is to learn
the fundamentals. Use your algebra-based physics textbook or 5 Steps to a 5: AP Physics 1 . There’s no
substitute for a thorough knowledge of basic physics principles. Don’t worry about calculus concepts,
don’t worry about the special Physics C–specific material, just work until you have the material down at
the introductory level. Even if this is the only exam preparation you have time for, you will be far better
served by shoring up your fundamentals than by grasping at more difficult concepts.
Once you are rock-solid on your algebra-based physics, then it’s time to think about the advanced
topics on the C exam.
A Word About Calculus
Yes, Physics C is “calculus-based” physics. And yes, you will be asked to evaluate a few integrals and/or
derivatives here and there. But it is vitally important that you understand that Physics C is not a math
course. The development committee is not trying to find out whether you know how to evaluate ∫ sin x · dx
. Rather, they are looking to see whether you understand how to apply calculus concepts to physics
problems. What do we mean by calculus concepts? Two things.
1. Recognizing When a Calculus Approach Is Necessary
In algebra-based physics you learned that the work done by a force is equal to that force times parallel
displacement. You will use that relationship in Physics C, too. However, in Physics C, you must recognize
the limitations of that relationship: you can only multiply force times parallel displacement when the
force is constant . If the force is changing, you must use calculus concepts, knowing that work is the
integral of force with respect to distance.
Physics 1-style situations, in which calculus is not necessary, will appear on the Physics C exam. Your
challenge is to recognize when a quantity is changing in such a way that calculus must be used.