Thread 16754680

Hey, Im currently a uni student (engineering), on my second year, starting in september. Last year failed physics 1 and 2. I do have to say that I never studied physics before (long story), so this is not surprising.

I however passed Calculus, DEQ, vector analysis (vector calc), linear algebra, and statistics, and some other classes unrelated (just saying Im not completely dumb).

So, my main issue with physics is solving problems, many times I just blank out and have no idea how to even start. I also can't just remember formulas without memorising them. Everyone says "you just have to understand them, not memorise", but many times on an exam I just can't remember it, so I can't solve the problem. Is the solution (for me) really just memorising?
Also, if the problem is completely new, I have no idea how to solve it, I really struggle with coming up with new solutions, I lose myself in the quantity of formulas there are

How do you tackle physics problems?

>>16754680 (OP)
1. Look for symmetries
2. Choose a coordinate system
3. Write down conserved quantities
4. Find equations of motion
5. Solve them

1-4 is usually done in class and you just have to transfer your knowledge from one problem to another.
To remember formulas look at the units.

>>16754680 (OP)
I genuinely don’t know how I made it through physics 1 and 2. Physics 1 was graded on a curve so iirc I only needed like a 60 to pass so I made it through that one.

>>16754680 (OP)
>How do you tackle physics problems?
Your story is familiar. I could always do the math, never the physics.
My majors went:
Math/Physics
Math/EE
Math/CompSci
Math/Stats
Turning a diagram and description into equations baffles me to this day.
I gave up! You can too!

>>16754692
>To remember formulas look at the units.
And always carry your units through. As a pure mathfag, I hated unit analysis. I would always drop them at the start and add them back in at the end.
This WILL NOT WORK!
This is literally how you lose a Mars probe.

>>16754680 (OP)
>I
>I
>I
Anyways, it seems your problem is that your math classes were too easy for you to pass and fail physics. Perhaps go to a proper university so you don't get tricked into thinking you know basic calculus?

>>16754692
yeah problem is my physics 1 prof at uni only shows ridiculous slides of the content, they don't do any problem solving (hated by all students)

>>16754692
equations of motion was the hardest for me at first haha

>>16754708
so by looking at units, you mean, remembering what each variable in the formula represents?

>>16754713
I dont think so, I have studied pre calc, etc, just no physics at all, I was like a blanc slate, while other students obviously had learned 90% of the contents in HS, the amount of new information was so overwhelming for me, we had like 12 topics to study in 3 months before the finals (physics 1)

>>16754730
Remebering: My answer is a velocity, so meters per second. My data is mass of two objects in grams and the distance between the objects' centers of mass in meters. Working out the units of the gravitational constant will help you remeber the relevant formula. And working out which formula you need will help you remember the gravitational constant.

Using in problem sets: The prof. actual wants the answer in lightyears per hour and the input masses are 80 gazillion furlongs apart. If you don't start using scientific notation and conversion units like a monk, you will fail. I was an anarchist mathfag and this was fucking kill for me.

>>16754680 (OP)
sounds like you need to practice more

>>16754734
Sorry, I've this happen too many times, i.e. students passing real analysis courses with flying scores, while barely managing to pass introductory classical mechanics and electromagnetism courses. And everytime it's because the math professors just slacked off and made their courses way too trivial.

>>16754680 (OP)
To start, do plenty of practice problems without looking at the solutions. When you start with a new type of problem, list out all the information you have in the form of equations, even if it may seem superfluous at first. Then, make the connections you think are necessary to solve the problem; go down each 'route' until you are successful.

The point of this is to gain intuition on what information is correlated to specific quantities, so that on the next problem (and so on), you can go faster and do less unnecessary formulations/calculations. If you read solutions first, though, you get an optimized 'route' through a single type of problem without developing this intuition, hence why I suggest suffering the trial and error process yourself.

>>16754810
No one even motivates the little maths they do teach.
Here in the US, where we stopped teaching anything other than arithmetic 35 years ago, we don't even motivate that with, "Cuz how ya gonna do yer gotdamned checkbook, homez?" because it's all literally an app on their phone that no one understands anyway.
It's all, "Twerk TikTok and U'Stock Do Pop".

>I'm currently a uni student

Stopped reading there.

University is for nutty academians who know nothing about life but use Government force to aid their social structures and enforce their stupid education on others while the world and those who don't accept the system suffers.

>>16754680 (OP)
It's really easy.
1) Draw a picture, usually a force diagram
2) choose coordinates, the thing that the force arrows are all touching is usually the origin
3) apply first principles, such as F=ma
4) solve

If you still can't hack it, then you can at least become an accountant.

>>16754828
Anarchist Mathfag, not OP
>1) Draw a picture, usually a force diagram
???
>2) choose coordinates, the thing that the force arrows are all touching is usually the origin
Honestly, as the scientist, as the observer, as The Physicist; radial coordinates with me at the origin is the only acceptable or feasible system. Prove me wrong.
>3) apply first principles, such as F=ma
Dude, wut?
>4) solve
EZPZ Lemon Squeezy
>>16754680 (OP)
>If you still can't hack it, then you can at least become an accountant.
OP, seriously. Start taking the actuarial exams. Once you hit CPA-level you can coast, or you can continue up to FreeMoneyMason level and work for the International Lending Banks and shit.

>>16754826
>i paid them to teach me a system and i didn't learn
>let me tell you all about it in musical form
Kek

>>16754754
thanks for the genuine advice!

>>16754828
vro its not just 2nd newtons law, thats only like 30% of the content, rest is fluids, thermodynamics, statics, momentum, etc... If it was just doing basic boxes with drawing arrows I would've passed

these are the contents for our physics 1 class
1. Mechanics of the Particle
2. Mechanics of Systems of Particles
3. Elasticity and Fluids
4. Oscillations and Waves
5. Thermodynamics
(with subtopics it's 10 in total)

we're not allowed any notes or formula sheets on the final exam. the final exam determines if you pass or not
and it's calculus based, don't know how it is in other countries, ppl who came here to study say our's is way harder

But Im not trying to justify failing. I will pass this year for sure :)

>>16754912
It's all the same bub. It all comes back to first principles.

>>16754920
no formula sheet is kind of aids
isn't physics empirical? you can't really just derive stuff on the fly from first principles like you can in a pure math course.

>>16754994
Idk man ask our professor.

Nah don’t
Its useless

He will just stare at you like you’re retarded

>>16754680 (OP)
First, I think a conceptual refocus is important: physics is a mechanical way of studying the world, and not necessarily of 'deriving' from first principles why that force is that way.

Stuff like normal force and friction force is stuff solved for, essentially. This is why 'memorizing formulas' doesn't work, because they may apply in different circumstances than what your system requires.

In physics 1, your goal is to write the mechanical system, break down the system into all its components, and solve for that system, how it moves, etc. So practice your free body diagrams and how to solve for forces based purely on Newton's laws as these are the fundamental universal laws.

>>16754680 (OP)
>Everyone says "you just have to understand them, not memorise",
Correct
>Do you want to look like a powerlifter?
Dumb fuck lol

>>16754692
>look for symmetries
>choose a coordinate system
>write down conserved quantities
all should be one step tbdesu. and ideally practiced enough to where it's instant.
>find equations of motion
>solve them
really this methodology (reducing a problem to a known model and solving based on initial conditions) is like the entire point of a physics education. it's like two steps removed from all the lower level math courses you took -- the only difference is translating real-world ideas into manipulable quantities.
>>16754708
>as a pure mathfag
as a fellow pure mathfag (double majored in physics), i always thought units were super elegant and missed having some kind of contextual grounding for the more abstract coursework. analysis, group theory, rep theory, etc. all felt like my prof was just schizo rambling, no different than fat tabletop nerds arguing over their game's magic system.

>>16754680 (OP)
>>16754692
hijacking this thread
completed calc I-III, the calc based early physics, this semester is going to be mechanics, "modern physics", and EM.
My mechanics professor stated a healthy knowledge of proofs is required.
I haven't done a fucking proof since geometry in high school. am i fugged?

>>16754994
most mathematical derivations you learn come from physicists

>>16757481
proofs' easy just think a little

>>16754680 (OP)
You didn’t learn from your mistakes. That’s it really.

- Can you do the homework questions? Cold, without reference. If you can’t even do your homework, how do you expect to solve the exam questions?
- How long does it take you to solve a question? Unironically record your attempt. Like video recording. And identify the hotspots. Speed is important in exams. Certain steps should be borderline automatic. Drawing accurate free body diagrams, differentiating the terms, trigonometry and algebra manipulation, etc.
- Compare your solution/attempt to the model solution. Spot the difference. Identify your misconceptions. Knowledge gaps. Missing steps. Careless errors. Forgetting facts and formulas. That sort of thing. Take notes. You should remember your mistakes.
- Do the same with textbook problems.
- Do the same with problem books.
- Do the same with the exam questions that you failed.
- Do the same with old exams you can get.

In case it’s not obvious, this is less “studying physics”, and more studying why YOU can’t solve the physics problems. Within a reasonable time.

Doing more problems is the most efficient way to do this.

>>16754680 (OP)
>>16758262
There are a few problem solving books for undergraduate physics. Feynman’s Tips, Belikov, Oman & Oman, Dimitrij Tschodu (kinda, more like study tips, think Cal Newport’s earlier books). I don’t recommend them. I don’t think they are useful in your case. But who knows.

I think math problem solving books are more useful. Polya, Paul Zeitz, Larson, Mason.

Not OP, I'm in a chem track but I'd like to get my masters in physical chemistry. I did super well in newtonian mechanics and electrodyanmics/maxwell's equations, but as soon as we started doing lagrangian mechanics I dropped the ball. any advice?

>>16754680 (OP)
>>16758285
I can’t believe no one said this. But stop being a 4chan loner weirdo. Ask the smart classmates who did well how they did it. Make some friends.

>>16758295
Well you see, I did that, and got told they "read the text book, did the practice problems, and showed up to class." I did those things, except I still struggled with the practice problems. I was wondering if someone had an actual resource to help someone who has tried and failed.

>>16758175
but me smort, not smort smort
me think only kind of gud
me no member ez

>>16758312
>I did those things
No, you didn't. You think you did but you didn't.
>except I still struggled with the practice problems
Everyone at all level struggle with problems. Either practice your basics, do easier problems, or get help.

>>16758312
There is a difference between reading a textbook passively and reading it actively.

You don't want to be nodding along with what you are reading, you want to understand it, crack down all the details of what it is explaining and then replicate it yourself, and that should show up in practice problems.

It's more frustrating and more time consuming this way, but that's how you do it.

>>16758740
I apologize, anon. Could you pick a textbook that you have and apply this approach? Like pick a paragraph, formula, lemma, etc. I'd like to see an example.

>>16758295
I'm the one people asked. It's honestly a skill issue. They consistently viewed me as some math genius just because my work was clean (I had thrown out all the scrap paper full of errors). I learned that these folks were just in a different intelligence class than I was. For the record I never read the textbooks, didn't take notes in class, and only solved the homeworks in preparation for the exams

>>16758999
>They consistently viewed me as some math genius
You can’t detect sarcasm and mockery. Signs of autism.

>>16759026
Very funny. Your insecurity is showing.

>>16758295
'Im too smart!'
>didn't read book
>didn't take notes
>did homework last minute
'Why did I do badly later on???'

No one cares about your natural intelligence or if you can pass with poor studying. They care about if you can do the subject.

That may require more work than others at various points, but at some point you won't be the smartest and will need to study.

>>16759258
Please stop larping as a good student. It’s off-putting.

>>16759265
Lmao, might not believe it but some are. Im just saying the answer to your conundrum is right there.

>>16758721
>No, you didn't. You think you did but you didn't.
smug and unhelpful
>Everyone at all level struggle with problems. Either practice your basics, do easier problems, or get help.
The problem I have is the easy 1-step problems are exactly that: easy. I can do most of the simple problems but I still struggle with the multistep problems and I don't know why.
>>16758740
I understand what you mean, but I've been through the relevant parts of the textbook a half-dozen times. As I mention in my reply above, I've got a grasp of the content well enough to do the simple one-step problems, it's applying interconnection in multi-step problems I'm having difficulty with.

intro physics
>write knowns & unknowns
>look up eqn
>plug & chug
upper level physics:
>start with eqn
>apply well known mathematical operations
>apply limiting cases
>voila! result!
grad level physics:
>write lagrangian
>use calc of variations
>result!
>write down dirac/klein-gordon/etc. eqn
>apply green's functions for brain dead solution
>result!
look, this is all an IQ filter.
>intro needs at least 115
>upper level needs at least 130
>graduate needs at least 145

When you talk to people who’re good at contest math, competitive programming, and so on, they almost always will say to learn from the solutions. As in spend 10-30 mins at a problem, and look at the solution. Don’t waste time “thinking” and “staring” at one problem. I think a lot of students are too idealistic in their approach, without the aptitude to back it up. Stop perusing the text, skim it and just go straight to the problems. Find texts with solutions, either included officially, pirated instructor’s manual, or online 3rd-party solutions. The last one is usually available for classic textbooks.

Well, that’s the standard advice anyways. It obviously works, but most people won’t do it. I’ve told retarded classmates what to do to pass the courses. And they still didn’t do it. I used to think some people are just born lazy. But now I’m older I can see some people just have shit mental health. You probably do too. Unfortunately, there is no fast way to fix it. It’s probably something like Step 1: quit 4chan, Step 2: do CBT workbook, Step 3: find a therapist that you like.

>>16757332
>as a fellow pure mathfag i always thought units were super elegant
You see a multiplicative identity. A perfect 1.
I see 0.3937inches/cm. Dude. wtf?!?
We are not the same.

>>16758999
Sup. bro. Nice digits.
You sound like a younger me. Labeled as "gifted" rather than diagnosed as 'sperg.
A bit of advice from an GATE/PEAK oldfag: Let your anger go. You have talents and value. Use them to be happy. Let everyone else do themselves. Peace.

>>16759353
Considering Feynman's IQ was 125, this is a bit of a stupid way to look at things.

Not that there isnt some intelligence filter but if you're judging your ability or career by a number then get a life.

Maths is and always has been mechanical, procedural rule-based symbol manipulation.
Rigor, discipline, and practice will always outperform "innate ability", esp. when innate ability is code for monstrous social freak, with acne.
/thread

>>16759500
We are talking about how OP struggles with his physics courses despite passing the math ones just fine.
This is why I believe a lot of replies and posts on 4chan are just AI LLM bots these days.

>>16759493
believing feynman actually had a 125 IQ is also an IQ filter btw

>>16759522
>he said he's building a Lean framework for his F* front-end
>yeah, idk either
I've seen self-coded bots replicate like fractal branches in a Recursive Busy Beaver Simulator. All lost, like tears in the rain.

>>16759527
He took one and that's literally what he got.

IQ is a value gave based on how you did on test compared to others, put on a normal distribution. Its not some number baked into your soul, so arguing someone's 'true IQ' is inaccurate. You can argue someone's IQ doesn't reflect their true intelligence or had they taken a more accurate test, gotten a different one, but not their 'true IQ'.

Also, I think some fail to understand of how much rarer 145 IQ is to make it the 'default minimum' for PhD. Googling gives the average as 130 for physics PhD or so.

Point is, if you say Feynman getting 125 showed the test was wrong or not predictive, it only makes the argument for me, that it cant be inherently diagnostic and if you use that number to lead your life, you're an idiot. Use your actual abilities instead: that is what you'll be tested on.

>>16759667
>ol' dick, he liked to have a drink or two
>and the women, oh brother
>practically a communist, iykwim
He was smart enough to know when to play dumb. The military brass at Los Alamos hated him for making fools of them all.

>>16759667
There are PhD mills that drag the average down. Focusing on the minutiae of irrelevant details shows that you got filtered and felt upset. When you looked up the exceedingly high average IQ of physics PhDs, you confirmed the posts assertion that physics is an IQ filter. Thanks for playing, kiddo. Better luck next time.

>>16759731
>i don't have one either
We good.

>>16759731
That's an explanation you straight pulled out of your ass. The rest is just projection on your lack of research you also pulled out of your ass. But this board has such a braindead way of looking at these things.

This is an anonymous forumboard and so it's stupid to mention my personal life, but I'm the opposite of being filtered.

>>16758845
I may not respond if simply because I kind of want this to be the last post on this site as I don't see much value here for me, but I want to help if I can.

I haven't been studying as much as it was summer but I was working through Differential Topology by Guilleman and Pollack. At some point section 7 page 41) the Hessian matrix was mentioned with the statement that there exists tests that, depending on the determinant, gives you a max or min of your critical point. I didn't know why that was. So I tried to break it down myself: I knew I need a multivariable taylor series but I realized I didn't have a good impression on why that should be true: so I found a derivation for it, and now I better understood it. Now no matter how I looked at it, I got doubtful this was true and so googled and it said a Hessian being positive-definite or negative-definite was the determining quality and the determinant was indeterminant. Which was perfect because now I understood why the Hessian determined maxes or mins: essentially the 'second order components' were always positive so in a small enough neighborhood, would dominate: and as it is a critical point, first order components are 0.

I guess another recent example is when Evans book on partial differential equations cited a 'integration by parts' in multivariable case. I tried my own guess at how they did this and then I had the aha moment of it being a generalized divergence theorem, and then used that to show what they did messily. I then read the appendix where they proved the case.

Honestly worry I'm still not doing things the best but I noticed when self studying or even reading there is the bad habit of 'nodding along' and not trying to write down yourself how they do or derive things. But I also not getting obsessive is good so you can move on and finish what you're reading. I also have physics examples and one from Rudin but it may be less authentic.

>>16759889
I suppose for the physics example, there was a question about a car on an inclined traveling around with uniform circular motion without losing height. The goal is to find maximum value of velocity so you don't fall off.

Were taught the situation in the frictionless case and a question included friction. I remember rederiving the example myself and not understanding the following contradiction: My intuition was thinking that I can decompose the gravitational force into parallel and perpendicular components. As the car is not lifted off the surface, i thought, based on similarity with the incline plane problem, that the normal force should cancel the perpendicular gravitational force. But this lead to an issue: the static friction force acts parallel the surface, so if I use the condition of zero vertical force, the car would have no force.

What went wrong? Put simply, the intuition on the normal force was wrong and I worked on why this was: essentially, the idea of a normal force canceling against the surface is only logically derivable in case of a flat surface. But it does not hold in case of curved surface, because our force can be inwards pointed which the curvature 'adjusts to' . Doing this let me better understand normal forces in their entirety as a constraint force, and how to treat it as a variable in a free body diagram. By looking actively to understanding my intuitions and rederiving, learnt a lot.

Others come to mind with this when it comes to friction.

>>16759909
This was in honors physics: I then took the regular physics: stupid online homework, scantrons, large class size and less conceptual. So I had a point of comparison.

All I can personally say is I think think these classes are horrible for teaching and understanding, and if you don't get it, it's going to be on you to break down the 'why' on lots of things, do external problems, just... getting a handle of the physics beyond formula memorization, because you're not going to be provided it.

>>16759889
>>16759909
you sound insufferably retarded. more words does not make you smart, nor does it make you sound smart. it reveals your chaotic and unstructured style of thinking (which, btw, is why you struggle with math and physics)

>>16759915
kill yourself

>>16759924
Marcus Aurelius tells me that you're angry because you know i'm right.

>>16759927
does it anger you? to know someone is better than you? why you waste your life on here to convince you're better?

im just trying to help and give the feedback requested and you in your retardation make it something else.

>>16754680 (OP)
I don’t know about you. But when I was in university, they showed the final exam’s score distribution to the class. Most people are just not good enough for physics. You’re one of them.