What is Physics: Definition and 990 Discussions

Physics (from Ancient Greek: φυσική (ἐπιστήμη), romanized: physikḗ (epistḗmē), lit. 'knowledge of nature', from φύσις phýsis 'nature') is the natural science that studies matter, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over much of the past two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the Scientific Revolution in the 17th century these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy.
Advances in physics often enable advances in new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.

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  1. J

    Chat GPT asked me to speak to some real physicists is why I'm here!

    Hi all. Started a conversation with Chat GPT about the big bang, C, gravity, time, thought experiments and other things that I mull over in my brain every few months and it suggested I talk to someone that's actually studied some of the things I asked about especially as things change...
  2. P

    B Looking for help understanding string theory

    String theory is a vast topic, and no grade 9 book will have content on it. However, no site or video gives it the attention this topic deserves, please input your understanding of string theory here. here are a few general questions to think about: 1)What is string theory? 2)Why was it made...
  3. V

    Solve Simultaneous Equations: Loop/Junction Eqns

    +1.56 - 43i1 - 75i2 = 0 +1.6 - 100i3 - 75i2 = 0 +i1 - i2 + i3 = 0——-> i1 + i3 = i2
  4. ab200

    Destroying a Building Using a Lens

    Putting the questionable nature of my professor's problem-writing aside, I found this question pretty confusing. I assumed that 60 m was the focal length, and that R1 was infinity since it is a flat surface. This gives me: 1/60 = (1.5 - 1)[(1/∞) - (1/R2)] This gave me R2 = 30 m, but that isn't...
  5. L

    From Physics to Engineering: The Career Journey of Leslie Rhorer

    My name is Les and in 1977 I began studying Physics at Texas A&M university, After four years, I decided a career in Physics was not for me. Since then Ihave been working as an Engineer.
  6. kuruman

    Speed of cylinder rolling along a horizontal surface gathering snow (Solved)

    This is a spin-off of a similar problem posted here in which the cylinder gathers snow as it rolls down an incline. I think one has to understand the snow-gathering process before attempting the more complicated case. A horizontal surface makes that easy but because it is a different problem, I...
  7. immortalsameer13

    What is Quantum Theory and How Does it Apply to Classical Entities?

    hello! my name is Mohammad Sameer from India. Pursuing five years integrated masters in physics, will be starting my second year in couple of days. Interested in quantum theory of classical entities and want to explore more in the domain.
  8. Trysse

    I Three inertial particles: Separating the twins from the paradox

    This is a response to a recent insight article regarding the twin paradox. The idea is to model the most basic scenario in a way, that the paradox disappears. This basic scenario and its kinematic effects are then modeled using only a straightedge and a compass. The best way to read this post...
  9. AlbertX

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    Hi, My name is Albert, and I'm here to learn and share knowledge and experiences throughout my journey in physics and human sciences.
  10. D

    I Observer on Earth watching a spaceship traveling at c/2

    i have just started on relativity, so be simple. you are going to travel 1 lightyear at half the speed of light. therefore, it would take 2 years to travel 1 lightyear. on Earth, you would see me going half the speed of light, so it should take two years as well? i calculated gamma as being...
  11. R

    When is the distinction between science fields applicable?

    Something I have been thinking about and don't really have a good answer to. For context, let's take physics and engineering for example. From my understanding, a very rough definition of physics would be the study of naturally occurring physical phenomena and understanding how they work...
  12. D

    What sparked Dorian's interest in physics and led her to PF?

    I'm supposed to enter a valid message so here we go. I'm a girl obv and very much interested in physics. Found this platform on google and thought it might help me quench my thirst of ever growing curiosities. Yea, that's it pretty much
  13. O

    High school physics problem sheets and tests

    I'm a retired physics teacher who taught physics and AP physics for maybe 40 years. I saved my problem sheets and tests. If you are a beginning (or experienced) teacher and need pre-made problems and tests I'll send you mine. I'll wait a few months for a reply, then to the dumpster they go...
  14. L

    Asking physics questions based on very little information? (YouTube videos)

    Is there a category to ask physics questions based on very little information? Namely a YouTube video that discusses a topic in a way that confuses me that I merely want clarification on?
  15. Zycraz

    Need Help with Physics? Get Assistance from PF's Community of Experts!

    I need one since im about to enter university next year and i didn't have so much physics in HS so i might need a bit of help
  16. Arohan

    What is the Connection Between Mathematics and Physics?

    Math grad, crazy about physics!!
  17. advhaver

    Admissions PhD Programs for Mathematical Physics (Experimental Condensed Matter Physics)

    HI, I am an International Student studying in the US (at a "liberal arts" small college ranked in the Top 20 as per US News Rankings). I will graduate in 2024 and intend to apply for PhD programs in Mathematical Physics starting October 2023 for admission in 2024. GPA: I am a double major in...
  18. Ranku

    I Gravitational Force Calculation w/ Superposition Principle

    Consider an object which is constituted of two different materials, which are inseparably mixed together, but which have different magnitude of masses. To calculate the gravitational force of the object upon another object, can the superposition principle be applied to the two constituent...
  19. MadAce

    I Game Design: Set rigid body into a position (Euler angles) using angular velocity

    I apologize for messy title, but that's as short as I could make it to say all that I wanted. I also apologize if I'm not using correct math phrases, but I'll try to picture a problem the best I can. I've been pulling my hair out trying to solve a problem I'm having for couple of months. The...
  20. MadAce

    Hello fellow game physics enthusiasts! (I hope there are some here :D)

    Hello! I'm from Croatia and one of my pass time obsessions is game physics, especially ragdolls, and any game that lets me play with that is a game for me. I did some mods for games like Fallout New Vegas which modify how physical objects in game work which seem to be popular. Anyway, I hope...
  21. JessPlaysGames

    I haven't studied physics for a while, and looking to get back into it

    I’m Jessica, a (nearly) 25 year old trans woman from the UK. I studied Physics and Astrophysics at university before dropping out. I dropped out for mental health reasons which were later diagnosed as Gender Dysphoria. After a few years away, I have now begun tutoring Physics to a friend in...
  22. amoonaa

    Admissions Can I do PhD in Physics if I have Bachelors in Engineering and 14 years of industry experience?

    I have bachelors degree in electric engineering and masters in engineering management and 14 years of experience in software product development. So no experience in physics at all. Is it possible to do a phd in physics ? Its always been my passion that i now think about pursuing
  23. P

    I Forces and gravitational time dilation

    The following is more of an interesting example and observation than a question that I am presenting for public comment. It's somewhat related to a recently thread, which was closed for moderation, but I think it's different enough not to fall under the ban of reposting threads that have been...
  24. Slimy0233

    Calculating Average Acceleration of a Particle Moving in a Circle

    I was given two HW questions, I was supposed to solve on using ##<\vec{a}> = \frac{\vec{V}_f - \vec{V}_i}{\delta t}## and another using ##<f(x)> = \frac{\int_{x_1}^{x_2}f(x)dx}{x_2 - x_1}##, I was able to solve using the first formula but I wasn't able to do it with second (at least I got the...
  25. ohwilleke

    I Are non-perturbative methods in physics limited to quantum physics?

    Non-perturbative methods are critical in parts of quantum field theory, such as QCD, and have at least some applications in quantum electrodynamics. You can also have mathematical problems that don't have perturbative solutions. But, it isn't clear to me if classical physics can ever have...
  26. Ben2

    Solving Rotary Friction Problem at Ye Olde Swinging Door

    Homework Statement: A door opened at 75 degrees from the latch remains at rest. When moved to a position 60 degrees from the latch, it slowly closes on its own. Is there another possible cause besides a sloping floor? Relevant Equations: \tau = r x F; v = \omega x r; a_T = \alpha x r, where...
  27. E

    Signs of work done and delta K.E.

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  28. CuriousGuy33

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    I am planning to take undergrad physics but I am concerned about the pay scale of physicists. Since I am the leader of my family (after my father), I will be financially supporting my family soon as my father retires (we have a family system). I also will have my wife and children. The reason I...
  29. L

    Show that an operator is Hermitian

    Hi, unfortunately, I have problems with the following task I tried the fast way, unfortunately I have problems with it I have already proved the following properties, ##\bigl< f,xg \bigr>=\bigl< xf,g \bigr>## and ##\bigl< f, \frac{d}{dx}g \bigr>=-\overline{f(0)} g(0)+\bigl< f,g...
  30. Q

    Physics IA: Distance B/w Pendulum & Alum. Block, Finding Damping Coefficient

    TL;DR Summary: I am doing an experiment for my Physics IA and don't know the theory behind it I am working on a Physics experiment for my school where I vary the distance between a simple pendulum and an aluminium block, and get the damping coefficient for each distance. Below are the images...
  31. P

    How Can I Relearn Misunderstood Concepts in Physics?

    My understanding of certain topics in physics has been flawed so now trying to learn it all over again. The internet is a fantastic place to relearn misunderstood concepts.
  32. ForTheBit

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    Hello everyone, I graduated a few years ago with a bachelors in aerospace engineering with a 3.2 GPA and a second author on a published research paper. I am currently working as a senior software engineer, but have been considering going back to school for a PhD in Physics. I am planning on...
  33. Lil123

    Solve Disk & Coil Spring Motion: Get Amplitude Help

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  34. Amsalja

    What is Velocity.length_squared?

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  35. T

    How to write Equations and Symbols in the Homework forum?

    Homework Statement: . Relevant Equations: . How do I write equations and symbols in the homework statement and relevant equations sections?
  36. Saint Elmo

    Can a Non-Expert Understand Complex Physics Questions?

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  37. nohtha

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  38. Astroparticle

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  39. jaketodd

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  40. A

    Other Math Help for Physics Undergrad: Advice Needed

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  41. S

    How is Physics taught without Calculus?

    I remember taking Physics in high school, so I guess it is possible, but it's been so long ago, I can't remember. It just seems that Calculus is indispensable when teaching Physics topics, except for a few like heat expansion or geometric optics. I would imagine that there is a lot of Δ this &...
  42. JackNicholson

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  43. taabut

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  44. taabut

    What's New in the World of Physics? Join Our Community and Find Out!

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  45. makamo66

    B Why does torque increase with increasing moment of inertia?

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  46. abayerle

    How Does Alex Contribute to X-Ray Mirror Research in Physics?

    Hi everyone, looking forward to meeting people how like to think about physics and discuss, solve problems!
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