Struggling in Physics! Plz hepl!

Main Question or Discussion Point

Hello I am currently a high schooler in AP Physics C (Calculous based), which the equivalent to first year of physics in college. I am really struggling as my foundations are weak especially in this Electricity and Magnetism stuff we are doing this semester. Can anyone recommend me some good readings or anything to get or some way I can get on the right track. The book is alright, but a lot of the things I don't understand what the chapter is saying. Pure memorization of the text and equations is obviously not working. I just need a push in the right direction so I can feel much more comfortable with whats going on.
Thanks again! (:

You should first understand calculus thouroughly before tackling physics courses .

jhae2.718
Gold Member
... Pure memorization of the text and equations is obviously not working...
I found the Princeton Review AP Physics C guide to be helpful.

However, you shouldn't be trying to memorize things. You want to have an understanding of the concepts, not just be able to regurgitate information. Memorization won't help you on the AP Physics C exam (for the record, I took it and got a 4 on both the mechanics and E&M parts; not particularly my best job, but not too bad).

Now, this is much easier said than done. I'd say that the only way to get better is to do a lot of problems. Over time, you develop an intuition to solving them.

Start with the basics. If you lack the calculus background, you'll want to improve that first. Physics requires you to have a solid math background. Practice with vectors, dot products, and cross products. Be familiar with differentiation and integration.

Then, start looking at the basics. Before you look at E&M, you should understand mechanics thoroughly. Start with kinematics, and work problems until it becomes second nature, then move on to dynamics, energy (extremely important!), etc. Then, when you understand these concepts, start E&M. Begin with Coulomb's law, move to the electric field, etc. Try to understand how the concepts are related, e.g. $$\vec{E} = \lim_{q_0 \to 0} \frac{\vec{F_E}}{q_0}$$ (E is electric field, FE is Coulomb's force, and q0 is a small "test charge"). Learn how to derive formulas for acceleration, velocity, position, etc.

The key is understanding the concepts. You're going to have to work at this. See if you can get help from your teacher or a friend.

Honestly I'd work on understanding your calculus before anything else. You can be an expert at calculating derivatives and integrals and still struggle in basic physics because you don't really understand how to set up problems using calculus. (my first year E&M class is learning that the hard way right now). Also never EVER just memorize things if you can help it. Always seek to understand. When you understand why a method works, you'll find that all it takes is a little practice to become a master at applying it. You'll be much better off than if you try to strictly memorize a method.

Thanks everyone! I am currently taking calculus ab ( should have taken bc) and yeah I am pretty good at integrals and derivaties, but I haven't mastered it yet. I think my main problem is I lack the basics, so there is no possible way I can set up the more difficult Physics C problems.

What's probably biting you isn't lack of foundations. Nearly all the physics I'm doing in my college intro physics class is based on addition, subtraction, multiplication, and division. The problem you have, like nearly all physics students, is that you don't have the first clue how to set up problems in terms of mathematics. You are likely quite good at math, way more than you'd need for AP Physics C. Even my college class really doesn't use calculus that much (though E&M is betraying its integral-heavy foundation already!) -- all you really need to know is knowledge of differentiation, integration, and the fundamental theorem of calculus. Okay, and a solid understanding of differentials and what they actually mean. Other than that, it's not the calculus that's killing you, it's the arithmetic you learned in elementary school.

The only thing you can do to remedy this problem is to do problems. Memorization and regurgitation is exactly the wrong thing to do in this situation. My physics professor flat out gives us the equations we'll need, and the class still has extreme difficulty with the material.

I would understand some of the key concepts of physics if I were you. Potential energy, work, force, conservation of energy, superposition (especially useful in E&M) -- these things are very handy. Go here and read, then go do as many problems as you can get your hands on: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Good luck.