I love physics so much, particularly mechanical and quantum physics, and I’m generally good at grasping new concepts and solving problems.

The thing is, I have tried to study chemistry from a notebook, and it was so much fun—even though chemistry is less interesting to me than physics. So, I decided to try self-studying physics from notebooks.

Where can I start? In my school, we study from Physics by John D. Cutnell and Kenneth W. Johnson and College Physics by Serway (only some chapters from each one).

I am currently a sophomore undergrad pursuing a double major in physics and mathematics. I'm hoping to attend graduate school in theoretical physics with a special focus on research areas around Quantum Gravity and the foundations of QFT. What are the most important things to keep in mind when looking for good grad programs? Further, what sort of things can I do in the two years left of my undergrad to really strengthen by application?

I am looking at this paper for unsteady propeller blade loading estimation in non-uniform flow.
According to the paper, we can estimate the thrust of a propeller blade section in non-uniform flow by multiplying the quasi-steady thrust with the Sears function S:

https://preview.redd.it/tppg0mcbgl7e1.png?width=302&format=png&auto=webp&s=49c01442d5c2cb3c7c17956d1078c4124ff82352

r = radial section; sigma = reduced frequency.
The quasi-steady thrust is just the outcome of a change in the sectional advance ratio.
I am wondering if there's such a thing as "unsteady change in angle of attack" too, or that is only quasi-steady, thus entirely dependent on the change in local advance ratio.

I am looking at this paper for unsteady propeller blade loading estimation in non-uniform flow.
According to the paper, we can estimate the thrust of a propeller blade section in non-uniform flow by multiplying the quasi-steady thrust with the Sears function S:

https://preview.redd.it/tppg0mcbgl7e1.png?width=302&format=png&auto=webp&s=49c01442d5c2cb3c7c17956d1078c4124ff82352

r = radial section; sigma = reduced frequency.
The quasi-steady thrust is just the outcome of a change in the sectional advance ratio.
I am wondering if there's such a thing as "unsteady change in angle of attack" too, or that is only quasi-steady, thus entirely dependent on the change in local advance ratio.

Is there anyone with a four year physics degree currently working as a software engineer/engineer?

How long did it take you to land a job post graduation? Did you take a coding course or classes via Uni? Starting salary (if comfortable sharing) Also, any tips for internships etc?

n the D Alembert principle, the work done by the constraint forces are taken as zero (assuming holonomic constraints). What is the intuition for this? Is there a mathematical derivation from time independence to zero virtual work?

PS: one thing I kind of figured out was that the generalized velocity of a system is perpendicular to the gradient of the constraint, does this imply that all virtual displacements must be perpendicular to the constraint's gradient?

Hello,

I am a second year (currently in 3rd semester) physics student. I am really unhappy with my grades and my work. The first year went by and I thought I'll improve on second year, now a semester has passed again and I am feeling lost. There are people from my friend group who get 9.7+ GPA (on a scale of 10) while I am 7.7.

At first I used to think that grades don't matter but now I've come to realize that it does. Its not about grades, Its that I've seen that people with better grades are doing good in every field and area.

I feel like I can do it (I really like physics) but I need someone else perspective of what I am doing wrong (Like schedule, mindset, or anything). If there is any advice or if I need to tell more about myself just lmk.

Thanks

Hello! I’m currently a physics major with a math minor, but I’m considering switching to materials science as it’s one of the more physics dense programs at my school and doing a physics minor as I love physics a lot but I am not 100% sure if I want to do grad school. I’m worried about the job prospects for a physics student after my bachelors in the event I decide to not do grad school as everyone I talk to tells me that job prospects for a physics major are not great with just a Bachelors, but I love physics so much and I’m scared of how I will feel if I decide to abandon my physics major given how much I love it! Physics alongside math make me so happy anytime I solve a problem, understand a concept, can describe a concept based on the given formula, when I can explain to others a concept in a way they understand it and see them get excited over it, etc. I also did really good in my first physics class (got over 100 for my final grade) so I know I’m capable of doing well in physics. I’m just stuck on what to do and need help deciding. I don’t want to keep going in this loop of indecisiveness on what to do for my degree.

Any advice?

Thanks!

Hi, the title is as reads,

Just to give some insight, i really wasnt feeling up for college this semester after suffering from severe PTSD. I feel alot of burnt out, last semester I had a strong 4.0 my sciences but this one my physics is 81% which is so low, it equates to a 2.7 gpa. its really sad as i realized i changed the right answer from one of my exams.

But yea, i was hoping to be a dermatologist in the future but a family physican DO route seems most realistic now, im wondering if i should still go for my dream as a derm? if so what should I do?

https://preview.redd.it/7ykkk8i3qf7e1.png?width=1517&format=png&auto=webp&s=834850baf9c7cbdb2c62b2a9af64df2df46b5e00

I'm doing an assignment and I was going to assume that the laser was a He-Ne one but wanted to see if I could work it out from the initial equation that it gives me. Any advice or help will be much appreciated!

magnetism chapter

cross(v1, v2) := [
    v1[2] * v2[3] - v1[3] * v2[2],
    v1[3] * v2[1] - v1[1] * v2[3],
    v1[1] * v2[2] - v1[2] * v2[1]
];
magnitude(v) := sqrt(v[1]^2 + v[2]^2 + v[3]^2);
B_field(a, b, f, x0, y0, z0, I, dl_dir) := block(
    [dl, rc, rdash, rval, cross_product, mag, B],
    fdash : diff(f, x),
    dl : [dl_dir[1] + fdash * dl_dir[2], dl_dir[2] + fdash * dl_dir[1], 0],
    rc : [x0, y0, z0],
    rdash : [dl_dir[1]*x + (1 - dl_dir[1])*f, dl_dir[2]*x + (1 - dl_dir[2])*f, 0],
    rval : rc - rdash,
    cross_product : cross(dl, rval),
    mag : magnitude(rval)^3,
    B : [0, 0, 0],
    assume(mu_0 > 0),
    for i:1 thru 3 do (
        B[i] : B[i] + mu_0*I/(4*%pi) * integrate(cross_product[i] / mag, x, a, b)
    ),
    B
);
assume(r > 0);
assume(I > 0);
circular : B_field(-r, r, sqrt(r^2 - x^2), 0, 0, 0, -I, [1, 0])+B_field(-r, r, -sqrt(r^2 - x^2), 0, 0, 0, I, [1, 0]);
line1 : B_field(-inf, -r, -r, 0, 0, 0, I, [0, 1]);
line2 : B_field(-r, inf, -r, 0, 0, 0, I, [1, 0]);
ans : expand(magnitude(circular + line1 + line2));

the magnetic field of line1, line2 and circular wire (made using two semicircle) are superimposed on each other, solving the question which was asked.

the biot savart law is assumed, and the derivations are done over it.

Sorry if my english is a little off.

I am a 3rd year undergraduate student in physics. There is a course on Lie groups next semester but i am unsure if it will useful for me in the future. There is also a course on Fluid dynamics being offered but I am not that much interested in it.

My one concern is that if the course will be too difficult for me.I have taken courses in Group Theory, Linear Algebra, Analysis in one variable, & Curves and Surfaces in my 1st and 2nd year. I'm not sure if I have the prerequisite knowledge for this course . I've given the topics which are to be covered in the course below:

• Topological groups, Matrix Lie groups, examples of Matrix Lie group, the Lie algebra of a Matrix Lie group. • The Baker-Campbell-Hausdorff formula, Correspondence of Matrix Lie group and Lie algebra homomorphisms, covering groups, subgroups and subalgebras. • Basic Representation theory, representations of SU(2), SO(3), sl(2, C), su(2), the Heisenberg group etc., Schur lemma, complete reducibilty. • Manifolds and Lie groups, Matrix Lie groups as Lie groups, examples of nonmatrix Lie group, Haar measure on Lie groups.

Thanks alot for any suggestions.

I have 3 questions, 1) when i have the AC current of a citcuit can i just calcule V(t) of each element by aplying ohms law to the phasor of I? Just like i do to calcule I(t) from V(t) where V is the total voltage 2) this voltage of each element will be Vr(t) = sin(angle the complex number + tw)Vrmax where r is the element of the circuit (capacitor, resistor etc) 3) when i have the total V(t) and its given with an angle different from 0 in t=0 like V0sin(angle+wt) then i perform the calculations normally to get the current but now the current will be I0*sin(angle+angle of the current respect to voltage+wt)?

Hello there. I am just getting out of community college in the NOVA area and happened to get into both UVA and UMD for Physics Undergrad. Credits surprisingly transfer nicely to both schools. However, I can't decide which is the better option to pursue. I am looking to do Theoretical(typical I know) preferably in the "small stuff research" so Quantum, maybe particle/high energy, Nuclear, maybe condensed matter. Really just looking for good research at this point since that is kind of the big thing for grad school and because I just want to answer some cool questions at this point. I know UVA seems to have acceptable high energy, and medical physics which I thought was cool. But UMD is more nationally recognized for its research in theoretical physics. Which do you all think would be the better option. Ignoring tuition for now even though I get in state for UVA, and don't want to think about the debt for UMD : , (

I'll only have taken up to ODE and Linear Algebra when I graduate from undergrad. I was wondering if during a physics phd if people get to take math courses? That's not typical right? I wanna do more cool fun math like PDE's. Actually, if I want to take something like relativity, wouldn't I need to have taken differential geometry? How does that work? Do people typically learn the math they need within their physics classes?

Hello everyone! For some background, I’m a self taught SWE going back to school to get my degree. I started as an independent freelancer doing web development work, eventually got a “big break” at a FAANG, and now work at NASA on internal web applications. I love my job but I don’t find web development very interesting and would like to break out of it eventually. My job will pay for me to get a degree, so I’m currently planning a double major in Physics and CS (doing a computational physics focus to create overlap). I’ve been passionate about physics for a long time, and was relatively advanced in both physics and math in HS (calculus, calc-based mechanics and E&M, college level linear algebra, etc), so I feel like I can understand the math commitment involved. However, I’m unsure whether I want to pursue engineering or science, since both paths can be quite different. I feel like the CS degree could also give me an “edge” since I already have a lot of coding experience. I’m also very passionate about both and want to study them in depth, and I really want to work on physics research. However, it would take at least one more year. What are the pros/cons of doing a double major vs just majoring in physics?

I said that Tx = Cx For the sum of torques, I wrote tension torque = torque of the weight + torque of the beam I just can’t seem to get to the result my teacher found and it’s driving me crazy

Some background: I'm a freshman student at a community college, just completed my first semester with 4 online classes. None of these classes were Physics or math related, mostly english/history courses. I was able to get two A's and one B+ in the other three classes I took, but for my political science class Im pretty sure I got a D.

Just to clarify, I got a D not because the course was too difficult for me, quite the opposite. It was technically my easiest class, consisting of four assignments, some easy quizzes, and a final exam that was two essays. The reason I did poorly was because I usually forgot to turn in the assignment/quiz by the due date. At first I thought I was lazy, turns out I have ADHD. I started taking medication and immediately saw a difference in my ability not just to focus but to function as a normal adult. But too little too late, because the course's "easy" nature actually worked against me, since the semester was ending and the class wasn't giving out more assignments or quizzes, only the final exam.

So what should I do now? I want to be able to transfer to a four year university to get my bachelors in physics and then eventually be able to attend grad school, and while im not necessarily solely focused on going to Berkeley or Stanford, its still something I want to go for if at all possible. So does my D in a non physics related course affect my ability to apply to these universities? How can I explain that this was a result not of character but because of a mental disorder? Im extremely passionate about physics, and want to pursue it for as long as I can, but I also recognize that it's very competitive and I should tackle it realistically.

I'm currently doing a neuroscience undergrad intending to go to medical school. However, I have a special place in my heart for physics, and its always been a dream of mine to one day do a masters or PhD in physics. This would likely be far in the future, maybe once my future kids have reached my current age. However, I have no interest in doing more undergrad than I need to. Is it realistic for me to pursue a masters or PHD in physics having done a neuroscience degree in the United States or Canada? The key word there is realistic. I know this is technically possible, but is this something people find success with? For the sake of the argument, lets say I'd like to try for MIT. (I know this is a big goal, but I'd like to know what I can realistically aim for.)

So heres the deal, I think I have fucked my undergrad in Canada after 8 years even after transferring to an easier school after some mental health issues.

Here are my stats: I'm looking at about a C average grade. I have some research experience in a course where I was supervised and coded a simulation for gravitational wave signatures in binary black hole mergers and did some signal processing in a joint program with two other schools, culminating in a group presentation and a week long physics camp at one of the other schools covering cool hot topics in physics. I also am currently working privately with another professor in an unofficial (not for credit) capacity looking at some pen and paper work and some coding work to explore whether or not differential entropy is a useful quanitty for atomic/molecular processes and what can be gleaned from that. Finally, I've been a math and physics tutor for about 6 years for first year students privately and as a volunteer at my university. I do not have any papers or anything like that published.

As it stands now, I don't think that my stats are good enough to get into almost any graduate school for physics when I look at the requirements for admission. Am I wrong on that?

I plan on just graduating and finally finishing my undergrad this year and coming back to academia in a few years potentially as I just can't give up on my dream. I do genuinely think I am smart enough for it, but I just don't have the habits and ethic at this point. The idea is to try to find a job with just an undergrad in physics and then when I am a bit more developed as a person and as a student and more mature in how I handle responsibility, I come back.

So these are my two questions: Am I right that my stats just aren't good enough to make it worth applying for schools? (I've heard not getting into a good grad school can be pretty damaging for your career). If the first question's answer is yes, what are the common job prospects for someone who just has a bachelor's in physics specifically (not astronomy or anything, never even taken an astronomy course). Any help or feedback would be appreciated

The question asks for the magnetic dipole moment vector, knowing that the area of ​​the loop is A and vector B = Bz. The field is uniform.

For wires 1 and 3, their resultant is zero, obviously. For wire 2 it is also 4, and we know that Fm2 = - Fm4. How do I calculate the integral of dl for wire 2? I'm having trouble determining the sign and verters for sine and cosine.

I'm studying for an exam and an exercise I found reads:

>Suppose a bidimensional crystal with a square lattice of parameter a. In the semi free electron approximation, and supposing that the Fourier components of the potential acting on the electrons is:

>Vg=0 if h+k=2n

>Vg=V0>0 if h+k=2n+1

>Calculate the two lowest energy values in each of the points (0, 0), (π/a, π/a) and (π/a, 0) of the reciprocal lattice.

So I know to do this I must use the central equation, but I'm having trouble finding the degeneracy of these points.

https://preview.redd.it/alpsputoga7e1.png?width=334&format=png&auto=webp&s=208febdfce08d477b606936dd76e98e685f14d4e

From another exercise the teacher did in class, the first Brillouin zone is a square of side 2π/a, so (π/a, π/a) is on a corner and has a degeneracy of 4 with the points (-π/a, π/a), (-π/a, -π/a), (π/a, -π/a), and thus the vectors used for the central equation are G'1=(2π/a, 2π/a), G'2=(2π/a, 0), G'3=(0, 2π/a), and G'4=(0, 0).

The problem is I don't really understand the degeneracy, so I'm having trouble solving this for (0, 0) and (π/a, 0), so just an answer on how to find the degeneracy would be enough. Thanks

Two charges of -2.6 μC and 3.2 μC are placed at a separation of 13 cm. Determine the position of a point, Y, on the line connecting the two charges so that the total electric field is zero.

Apparently the answer is 48 cm [left of A], but I keep getting 119 cm ...

I'm looking for a book that deals with adding constraints to Hamiltonian mechanics. I've found some loosely presented ideas about using Lagrange multipliers but they tend to lack worked examples. I'm specifically looking at this with an eye to numerical methods since I'm looking to write a physical simulation on my PC. My gut feeling is that, maybe with some limits on the kind of constraints you are dealing with, you can keep the sympletic structure of hamiltonian mechanics while keeping to the submanifold of phase space defined by the constraints.

I already own Goldstein and it does have a section about holonomic and semiholonomic constraints in the Lagrangian formalism. But I'd like to be able to work in the Hamiltonain formalism.

I’ve been trying to decide my major choice between chemistry or physics, and I’m leaning more towards chemistry because there just seems to be more job opportunities in society. I would say I enjoy physics much more and I’m also good at physics, but I don’t understand what job opportunities a masters of PH D in physics would offer. Someone please let me know😭

we are finding out the magnetic fields given a wire, its shape and its end points.

we assume that the wire is placed in the xy plane.

the shape of wire is understood by the function f(x) and the end points will be (a, f(a)) and (b, f(b))

we compute for the following wire types

1. magnetic field due to infinitely long wire
2. magnetic field on the axis of a circular loop

we assume that the current is constant and positive, I

here is the maxima code to solve this high school problem

cross(v1, v2) := [
    v1[2] * v2[3] - v1[3] * v2[2],
    v1[3] * v2[1] - v1[1] * v2[3],
    v1[1] * v2[2] - v1[2] * v2[1]
];
magnitude(v) := sqrt(v[1]^2 + v[2]^2 + v[3]^2);
B_field(a, b, f, x0, y0, z0, I) := block(
    [dl, rc, rdash, rval, cross_product, mag, B],
    fdash : diff(f, x),
    dl : [1, fdash, 0],
    rc : [x0, y0, z0],
    rdash : [x, f, 0],
    rval : rc - rdash,
    cross_product : cross(dl, rval),
    mag : magnitude(rval)^3,
    B : [0, 0, 0],
    assume(mu_0 > 0),
    for i:1 thru 3 do (
        B[i] : B[i] + mu_0*I/(4*%pi) * integrate(cross_product[i] / mag, x, a, b)
    ),
    B
);
assume(r > 0);
assume(I > 0);
circular : B_field(-r, r, sqrt(r^2 - x^2), 0, 0, z0, I)+B_field(-r, r, -sqrt(r^2 - x^2), 0, 0, z0, -I);
assume(not(equal(z0, 0)));
inf_long : B_field(-inf, inf, 0, 0, 0, z0, I);
magnitude(circular);
magnitude(inf_long);

the output equations are

maxima output

maxima and other symbolic mathematics software can prove to be really useful when solving physics