general physics advice

[eldoctor]

First time taking physics in undergrad (didn't take it in high school either) and I am getting hammered by the simplest stuff. for those of you who were in the same position, how did you study? are there physics for dummies books that may help? I read and read and reread but the concepts dont sink in, and I never know which formula to use for a specific problem. First midterm is close... and i cant even solve a simple trajectory problem...

anyways, any advice is appreciated

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[Yudid]

You scared me w/ this thread.... My first physics class is going to be this monday

 

[Contrarian]

hmm, I never really liked physics either, but have you done lots of practice problems? With physics, it's not so much the reading, but the solving of problems that should help you understand the concepts.

 

[phience]

What, exactly, don't you understand about projectile problems? Maybe I could help you out. I'm in the class right now and just finished our first midterm.

 

[oran berry]

Many people have told me that the "Introductory Physics as Second Language" books are pretty good. The algebra-based one is rated on Amazon 5/5 and the calculus-based version is 4.5/5. Seems right.

 

[muhali3]

I'm using an MCAT prep book (Nova) for my Physics class. It works pretty well.

 

[Contrarian]

I'm using an MCAT prep book (Nova) for my Physics class. It works pretty well.

smart move. If I could do it all over again, I would have tried to do some MCAT prep alongside the corresponding courses. It might be even worth it to do the EK 1001 questions if you get a chance, since they aren't MCAT style, but seem good for solidifying conceptual understanding.

 

[tmac11]

I'm using an MCAT prep book (Nova) for my Physics class. It works pretty well.

I think this may help. The MCAT prep books will give you the basic concepts instead of having to read it through a dense textbook. After that, be sure to do a lot of practice problems. That's the only way to fully grasp the material and apply it to whatever situations are presented on your test.

 

[Tin Man]

The thing about physics is that it's not really about the equations (much like the MCAT). It's about visualizing HOW things react, and understanding the relationships.

Introductory level physics is kind of a joke as a practical science, because most of the equations you will be dealing with will not apply in the real world. For instance, when is a normal human being going to need to know about projectile motion in a world without air resistance and with a perfect acceleration?

The point is to see these basic relationships between, for instance, mass and gravity. Of course they aren't the only things there, but if you understand how mass is tied to gravity, and how acceleration is tied to time, and so forth, then you'll be doing fine.

What's the key? Do all the stuff you never did in high school because you thought you were smart enough not to need it. Like what?

Draw diagrams. Write out the equations every time you work a problem, even if you know them by heart. Understand how to break every equation down to its basic components. Do LOTS of practice problems, even if they aren't assigned.

At the end of the day, your goal is to learn relationships so well that, even if you are given vague variables and no equations, you can still understand how things work with each other well enough to figure it out.

Conveniently, this is exactly what the MCAT will be testing, when the day comes...

 

[FloatOn]

I have never encountered a physics textbook/manual that was good enough to learn from. Chemistry books, yes. Biology books, definitely. Math textbooks just suck in general. Examkrackers Physics did a decent job, but I also had just taken two semesters of calculus-based physics.

Honestly, just ask a friend in the class or a classmate to explain the stuff to you. Physics, to me, is just one of those subjects you need to see worked out in front of you. The person could show you each individual step, what to look for, shortcuts, etc. Books often skip a bunch of steps or condense calculations so you have no idea where numbers come from. You sit there for 30 mins wondering how a 4 turned into a 27.

 

[Jfz]

I feel you. i took physics in high school but the way my prof is doing things is completely new to me. maybe i just need to brush up on basic math stuff but he assumes we know half the stuff and breezes through it.

what textbook are you using? i'm using cutnell and johnson and it doesn't seem too bad at this point, appendix in the back is helping me relearn some basic math that i need to know

 

[physicsguy]

Hello Eldoctor. Being a mere (hopeful) premed myself, I really don't feel in a position to be giving advice on this forum. But as my username suggests, physics is the one thing I actually can do.

Believe it or not, back when I was an undergraduate even I had trouble with my intro physics class, so don't feel bad if you don't get this stuff. All of the things others have said here are excellent ways to study physics, but really there's one crucial thing to remember. Your performance on exams in physics is usually proportional to the number of problems you've done. Whereas in biology and ochem it's best to study the book, in physics you really just need to do problems like crazy.

The truth is, there aren't that many different types of mechanics problems they can give you. So if you do a lot of problems, you'll start to become extremely familiar with the template problems and recognize them in any permutation. Another thing you should remember is to never plug in any numbers until the very end of the problem. I know it's tempting to whip out the calculator and start crunching numbers, but if you leave the variables in until the very end, you'll actually learn a lot more, which will improve your test scores. Take the trajectory problems, for instance. This problem can actually be solved in closed form. Give me a projectile launched at an arbitrary angle, at an arbitrary velocity from any given height, and I can write the equation for the path traced out by it, calculate the range, the time of flight, and pretty much anything else. This means that the difference between the various projectile motion problems in your textbook lies mostly in the numbers that they choose to throw at you. Learn how to do everything algebraically, and the numbers are irrelevant. When I taught intro physics, I found that my students who started every problem by plugging in numbers tended to do worse on the quizzes. Mostly because I wrote quizzes that contained no numbers. Trust me I'm no exception, physicists love closed-form solutions.

Anyway, if you've got questions on specific problems, feel free to PM me.

 

[afugazzi]

As a physics major, I second that reading and rereading the book is probably a waste of time. Instead, do practice problems until your brain explodes. If you find a really hard problem, do it once until you get stuck, read the solution, and then try it again tomorrow. Here's some to start:
http://tycho.physics.wisc.edu/courses/phys103/fall09/practiceExams.html
http://www.physics.wisc.edu/undergrads/courses/fall09/207/exams.html

These are old exams from UW-Madison that I believe are open to the public. The material should be similar, but not identical, to what you're doing. (If you're doing E&M, and not mechanics, the classes are 104 and 208). For practice exams, do them in one sitting and then go over the solutions.

Really just do as many problems as you can get your hands on. Physicsguy is right that there are only so many different types of problems. Do enough and you will see the pattern.

 

[AlexMorph]

Practice, practice, practice. Learn formula manipulation, that will get you through half the problems right there.

 

[09javcar]

Physics is relatively easy. You just have to grasp the concepts and know the equations. The rest is just basic algebra. With projectile motion the most you'll do is multiplication. The first time I took physics was in 2007 and that went pretty well. I was in my junior year of HS and I managed to grasp the concepts. YES, it's difficult at first. I had really hard trouble understanding how a bullet shot horizontally would hit the ground at the same time as if I dropped a pen or something. You know, the bullet would have traveled a long distance before it the ground but physics proves it.

The best advice I can give you is to be open minded and forget everything that right now seems logical, ex. a heavier object falls faster than a lighter one.

Practice Practice PRACTICE!

 

[iMD]

eff physics. it's a class i simultaneously loved and hated.

that said, the mcat prep book supplement is a good idea. PRACTICE PRACTICE PRACTICE. that's all you will be doing when studying for the mcat so you should go ahead and get a head start doing it now.

 

[Dannyw]

For the trajectory problems learn to use the dot product . It's much easier than breaking down vectors into components.

 

[lstone13]

First time taking physics in undergrad (didn't take it in high school either) and I am getting hammered by the simplest stuff. for those of you who were in the same position, how did you study? are there physics for dummies books that may help? I read and read and reread but the concepts dont sink in, and I never know which formula to use for a specific problem. First midterm is close... and i cant even solve a simple trajectory problem...

anyways, any advice is appreciated

I had trouble as well when I first started. My advice: practice practice practice. Practice alone and practice problems with groups too. Working through problems, sketching the scenario, and applying equations with a group helped me a lot.

Also, for some reason, reminding myself this helped calm me down... the professor is giving you problems you can solve, somehow, and usually, there are many ways to solve it. All the information you are going to need is in the problem. Map it and see which equations fit best for the information your given.

 

[boaz]

First time taking physics in undergrad (didn't take it in high school either) and I am getting hammered by the simplest stuff. for those of you who were in the same position, how did you study? are there physics for dummies books that may help? I read and read and reread but the concepts dont sink in, and I never know which formula to use for a specific problem. First midterm is close... and i cant even solve a simple trajectory problem...

anyways, any advice is appreciated

Your approach to physics should be very different from your approach to biology. The point is not to absorb info but to keep asking "why?" Don't accept anything in physics at face value; if you don't understand it 100% go to your prof's office hours. Second, doing every single problem at the end of each chapter will help a lot.

 

[medfan303]

Hey, I strongly suggest watching all the physics videos here:

http://www.khanacademy.org/

Mr. Khan is a graduate from MIT (BS/MS in EE) and MBA from Harvard. He's just simply amazing at explaining concepts, I've been watching the chemistry videos (not physics) so I'm not sure how great his physics videos are but I doubt they are less than perfect. He has videos for all major subjects (chem, physics, calculus, algebra, etc.). Let me know if it helps

Also, physics is entirely a do by practice type of subject. You can't expect to have concepts sink in without actually trying PROBLEMS. For example, a neurosurgeon hot shot is driving a lamborghini moving at 95 m/s, and a cop car is chasing the lambo at 30 m/s but is accelerating at a rate of 5 m/s, how long would it take for the cop car to catch up to the neurosurgeon? If you try and work out problems like these (fyi I just made this one up) it will help sink in basic concepts such as velocity, acceleration, and how they relate to each other. Also I highly suggest visiting this forum and getting involved early on:

http://www.physicsforums.com

Make sure to also go to your professor's office hours. From personal experience, I got a D+ in physics in high school, but I was really stupid back then, because I didn't understand things and just blew it off. Needless to say I never picked up in my grades. I changed this in college and ended up getting A's and B's except a C in modern physics (quantum topics, etc.). Physics is definitely a cumulative subject (you need to understand from the beginning or your screwed). Start tackling this 300 lb physics offensive linemen now otherwise you will get crushed and be injured forever.

my 2 cents.

-Medfan

 

[eldoctor]

http://www.khanacademy.org/

I have to tell you, this is the greatest thing I have ever seen. I have already passed it on to my younger siblings.

Thank you everyone for all the very helpful suggestions. Next up for me: PRACTICE PRACTICE PRACTICE

 

[medfan303]

I have to tell you, this is the greatest thing I have ever seen. I have already passed it on to my younger siblings.

Thank you everyone for all the very helpful suggestions. Next up for me: PRACTICE PRACTICE PRACTICE

Glad it could help

 

[lorenzomicron]

For Physics, I recommend using "Schaum's Outline in Physics" which has a ton of practice problem that you can practice on which will have sufficient depth for any physics class.
I recommend getting a peer tutor or working with peer groups to work on problems.
If the homework is problematic, use "Cramster" to help solve the problems, but only if you have not been able to solve them yourself first.
Physics is not about using equations; it is about understanding why things happen. If you understand the conceptual principles, then applying the equations will be a routine matter.
Also the mathematical principles are highly necessarry, so if you find yourself weak in some area of math being used, please review it because otherwise it will be difficult to do the physics.
Hope you do well!

 

[s1lver]

Hey, I strongly suggest watching all the physics videos here:

http://www.khanacademy.org/

Thank you and I love you!

 

[MB333999]

use common sense to check your answers

 

[VTBuc]

use common sense to check your answers

^^^ yep. Can't emphasize that enough.

Also, for ANY class...if you partner with someone else and teach each other the material it becomes easy as pie.

 

[SparkleMotion]

I was in the same position when I took physics.

I started out absolutely terrible but then as I learned how to take the class I gradually advanced and I finished my first term with an A-. This was after doing really, really bad in the beginning of the class, so I was pretty excited about it.

Anyway, here are three tips that I generated by some brief reflection about how I figured out physics:

1) Numbers are not your friend. Finish everything without numbers and then plug them in at the end. Most likely you'll be getting the majority of your credit on exams from the physics solution rather than the numerical solution.

2) In order to solve any basic kinematics problem make a list of the five factors - Vi, Vf, a, delta t, and delta y. Do a preliminary checklist of what you know, and then think about any other information that may imply something that you can draw from. For example, it may be a projectile problem and therefore you know that acceleration in the x-direction is going to be 0. After you do this, keep in mind that you only need to know 3 of the 5 factors, and then you can easily find the other 2 by simply plugging in numbers to one of your equations. Also, remember that time is the way that you can connect the x direction and y directions. You will often have 2 things in the x direction, but 3 in the y direction and can then find time for y, which is also time of x, which allows you to solve the problem in the x.

3) Don't bother reading the text. Do your homework and if you run into any problems (which you will often), go to a T.A or your instructors office hours to talk through what you need to do. Don't go in and say "I don't know how to do this." Before you go get help you need to work through the problem as far as you can and then have a very specific question that you need to figure out in order to proceed. Walk in to your instructor and say, "I used X method to solve this which looks promising but I'm stuck because I can't figure out how take Y thing and find the next solution." When you try to solve your problems sets don't sit down and make one huge grind to the finish. You should be making several fresh attacks on these problems.