Physics Definition and 987 Threads

Ok, so here is what i am trying to do. Find apogee of a model rocket i built using a C motor, then i need to calculate terminal velocity, but something is not adding up, i get a really really high apogee, almost a mile. STAGE 1: I have a c6-7 rocket motor which provides 10N-s of impulse, and...

I am looking for good textbooks in physics, algebra, and trigonometry textbooks that are up to date and a good read. I heard that Feynman’s Lectures was really good. Is it still up to date enough? Any opinions?

I was modeling the dynamics of a vehicle for a project, and started doubting about the way of applying physics in this particular case. The thing is, I know the torque in the wheels from the torque the electric motor I designed do provide, multiplied by the gearbox ratio. I also know the...

Summary: doesn't this decrease entropy ? Cellulose is known for its hydrophilic quality, which can be explained from the polarity of its hydroxyl groups. We all know water can overcome the force of gravity through a piece of paper you put in the water. Correct me if I'm wrong but this is a...

Hi, this is my first time using the Physics Forums so please let me know if this question belongs somewhere else. I'm a senior undergraduate at a mid-size institution in the United States seeking to purse a PhD in High Energy Theoretical physics or Quantum Information/Computing. I'm aware these...

(I need help with the 2nd part as I can answer the theory part properly). For E=4 eV we can find the wavelength of emitted photon. E= 4 eV = 6.4087e-19 J Using E= hc/λ we get λ=310 nm (approx) My doubt is that this should fall in the Balmer Series but we know that the lowest wavelength value...

This is a homework problem of my grand daughter. The question is to find out the conditions of an object M on a slope with angle shown and applied force "F". I find there are 3 conditions, sliding up, sliding down and not moving. This is my work. I just want to get comments on my work: At the...

Where the fingers (extended) go first, then only the knuckles. Is it supposed to be more effective? I believe it will break your fingers instead. An example

The editors of high impact journal Nature Physics explain why the field of quantum foundations is important for physics. https://www.nature.com/articles/s41567-022-01766-x

I'm a researcher hoping to look at some papers on the technical aspect of water physics on a water slide. Does anyone have resources or pointers for me? Essentially, I'm trying to find the optimal amount of water needed to propel a passenger down a standard straight water slide, but I don't know...

My girlfriend is in her undergraduate biology course, and one of her professors said the following sentence: "Physicists are jealous of Biologists, as their field has been stagnant for years, with no new things to discover." I know this isn't true. I even got to argue with her about how this is...

Hello. I wonder about the most important secrets of physics today. Once it was the "secrets of atom". Countries were in a race to be the first to do "atomic bomb." For that reason, America started the Manhattan Project. Similary, do you know names of the most important developments of physics...

As I was looking for an example for a metric tensor that isn't among the usual suspects, I observed that the Cartan matrix I wanted to use is positive definite (I assume all are), but not symmetric. Are the symmetry breaks in quantum physics related to this fact?

Hello, I am currently preparing to learn the 8.01 course "Physics I" via the MIT OCW and I am trying to find an adequate textbook for that purpose. In the three courses that I have found, the first two use: Young, H. D., and R. A. Freedman. University Physics. which is quite expensive in my...

Hi everyone, I'm new here but I've come across PF many times as viewer while searching for clarifications and exercise solutions. I think this should be the right place to ask for advice. My background: 30-ish years old, got my BSc and MS in Electrical Engineering in 2017. The courses were...

The measurement for astigmatism is diopter. But what does 1 diopter of astigmatism mean? Thanks a lot if you help me figure this out!

Is there any specialize articles that talk about how Astronomy can help learning Math and Physics? In particular, how observational astronomy can help in the learning process of Math and Physics.

Hi guys! I'm a master's student majoring in nuclear engineering in graduate school. I have a few questions while doing research, so I'm writing this here. My research is simple. We conduct neutron analysis to convert a research reactor using highly enriched uranium into a low enriched uranium...

How hard is it compared to undergraduate thermodynamics? Is it harder or easier?

If you enjoy both physics/science and history like me, you may enjoy this video from the Royal Institution. It's about groundbreaking experiments (no theoretical physics); X-rays, particles etc. I'm only 45 minutes in so I haven't seen the entire video yet, but I wanted to share it...

I recently graduated last year with a BS in Physics. To say that it was rough would be an understatement. I started off my degree very well, getting nearly all A's and A-'s. My performance would decline for various reasons, though mostly due to mental health which spiraled and became a bad...

Hello, I'm trying to learn calculus, what books would you recommend? For a beginner.

Can I get an online bachelor in physics because I live in a country with law education rank in natural sciences

I live on a lake, and have for almost 3 decades now. Every year I watch shoreline changes, from year to year and shorter timespans, sometimes just days. The lake is large in surface area at 236 km2 (91 sq mi), but with an average depth of only 28' probably relatively small in volume for its...

I am going into my senior year of hs next year and I am meditating on what I should major in. I have a keen interest in physics but also a love of math. The field in physics I would like to major in is theoretical physics/astrophysics, and the pure maths I am interested in are diff, algebraic...

Hi Pfs, When Stephen Hawking proposed the idea of black hole information it appeared that information could be lost. it was a problem in GR which is a dererminitic theory. Knowing initial data and Hamiltonian tells you what was and will be. It is not the case in quantum physics. things evolve...

I have been experimenting with a minimal "toy" physics engine for JavaScript, called verlet.js but now I want to switch to a more versatile and feature rich engine. One feature I would like to use is the ability to assign a reference angle to a pair of segments (i.e. links, i.e. distance...

Hi everyone, After completing high school, I will enroll this fall at a 3 year technical school in China studying industrial robotics, but I still plan on getting into an undergrad physics program at a later time. (Some colleges can allow a transfer to their undergrad program after technical...

There is a recent article, see below, where an AI equipped computer viewed a classic physics experiment with a double pendulum. The AI algorithm determined some different variables to describe the motion. One problem with this is the AI suggested 4.7 variables - that I don't understand - but...

I was searching for some science forums online yesterday, so I could join one to learn and contribute back. The Forums that operate like early 2000 ones, and their goals are more aligned toward users than creating content for monster spiders. I am glad that I have ended up here now. I visited a...

Can you please recommend me some condensed matter physics study books and semi-conductor physics study books? Much Appreciated!

I was curious if there were any unsolved physics problems and if so which is the most important or intriguing. I have been meaning to contribute to the scientific field in some capacity and I think solving an unresolved issue in physics could do just that. Thanks!

Summary: I am just curious I know 🧐 Im coming up the end of intro university physics mechanics chapters. It has been quite enjoyable, especially chapters on energy, momentum and fluid mechanics. There’s so much information packed into these chapters though. I am wondering what was your...

If you were to rank potential components of a Physics Master's program, which do you think are the most important for preparing you for a PhD: courses, research, project report, thesis? Also I've seen programs ranging in duration from as short as 9 months all the way up to 2 years. How much...

Umm.. yes I think. Not sure what I’m getting into, but the pursuit of knowledge eh? Teach me please. I’m just here to share thoughts and bounce between fellow big brains. Haha this strange. Good luck!

I wasn't sure if I should post this in astrophysics or particle physics, so I'll try particle physics first, mods feel free to move it to a more appropriate forum. So I was wondering if hypothetical Strange stars exist, would the strange quarks arrange themselves into baryons (i.e. Lambda-0 or...

for (a): I basically got the correct answer, but when resolved with taking different reference lines/frames I got a different answer. for the 1st attempt I took y = 0 (for both ##U_{el}## and ##U_{grav}) at the position where the spring is uncompressed. for the 2nd attempt (with wrong solution)...

Trampolines are in effect coupled springs, with the mat being the much softer spring generally. E.g. On my Acon, when jumping about 1 meter, there is a max cone of depression about 60 cm deep and 1 meter across (1 meter point has a depression of only about 10 cm) At this same point the 160 or...

Free Kindle via Amazon, both part 1 and part 2 Part 1: https://www.amazon.com/dp/B00OD49Z96/?tag=pfamazon01-20 Part 2: https://www.amazon.com/dp/B00OD49Z00/?tag=pfamazon01-20 Enjoy

Hey y'all, I'm starting college as a Physics major this fall and I started working through Steve Warner's Pure Mathematics for Beginners in my downtime because I love the math courses I've had, wanted to learn more about proofs and how those things came to be, and most importantly had nothing...

Adam Marsh's Mathematics for Physics is available online. Subodh Patil recommends the algebraic topology section, and as a primer to Nakahara.

https://www.feynmanlectures.caltech.edu/I_10.html (From the paragraphs after equation 10.5) 'It is not just a definition to say the masses are equal when the velocities are equal, because to say the masses are equal is to imply the mathematical laws of equality, which in turn makes a prediction...

Do they really teach and help anything? I am taking them for my nanoengineering undergraduate program. The textbooks are solid state physics by j r hook and concepts of modern physics by mcgraw hill and r b singh introduction to modern physics and introduction to quantum mechanics by david j...

Hello, Can someone recommend me a good textbook to (self-)study aerodynamics, optimally with focus on aircrafts. I am a graduated student in physics and therefore familiar with all the basic concepts of fluiddynamics and calculus. But, apart from that, I have no further knowledge in the field...

Hi I'd be grateful for views / thoughts on whether there was potentially a particular event, change, set of circumstances etc which could cause localised variations in the laws of physics (as we understand them). For example, you could be traveling somewhere, when you unexpectedly chance upon...

I will try to keep this concise. I have always loved physics, but was convinced by my parents to pursue biology for career in medicine. Over my undergrad, it really became clear to me that I love physics, and want to pursue a career in the field (a Master's, and then a PHD). I am currently in...

Halves-lives and average lifetimes, when studying nuclear decay, are often expressed in years even though years are not standarized, at least in SI (as far as I know). Borrowing the convention from astronomy and astrophysics, I usually take 1 \mathrm{yr} to be equal to 365.25 days of 86400...

I have a math degree and currently pursuing a BS in physics, I've been offered a job as a data scientist with occasional machine learning stuff. 1) Would this be helpful for my career in physics? If yes then how? (I'm aware that machine learning is being used in various areas of physics, but...