What is Mechanics: Definition and 999 Discussions

Mechanics (Greek: μηχανική) is the area of physics concerned with the motions of physical objects, more specifically the relationships among force, matter, and motion. Forces applied to objects result in displacements, or changes of an object's position relative to its environment.
This branch of physics has its origins in Ancient Greece with the writings of Aristotle and Archimedes (see History of classical mechanics and Timeline of classical mechanics). During the early modern period, scientists such as Galileo, Kepler, and Newton laid the foundation for what is now known as classical mechanics.
It is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light.
It can also be defined as a branch of science which deals with the motion of and forces on bodies not in the quantum realm. The field is today less widely understood in terms of quantum theory.

View More On Wikipedia.org
Recent contents Top users
  1. S

    Rotational Motion in Newtonian Mechanics

    Homework Statement Given an plate that has 2 pins attached to it. Each pin has a single balanced circular disc firmly attached to it. Each pin can rotate on their axis in both clockwise and anti clockwise direction. (See image below) Now, assume the discs are rotating with the same angular...
  2. Z

    Studying Is it possible to understand quantum mechanics in student life?

    QM is gradually conquering my mind day by day. i can't think anything expect it. i always thinking while eating,before sleeping,in classroom,while outside. my college performence is badly affecting as QM is not in my course. i just want to understand anyhow_could anybody guides me to understand it.
  3. S

    What is meant by natural frequency?

    An object only undergoes an oscillation when I act on it. If I push a spring, it will have a certain frequency, and if I push a different way, it will have a different one. What is meant by natural frequency? What is meant by resonance?
  4. PrathameshR

    Use of Lagrange's equations in classical mechanics

    I have been studying classical mechanics for a while from Goldstein book and can't go ahead of the following derivation. I understand the method of Lagrange's multipliers for getting extrima of a function subjected to equality constraints but can't understand it's relevance here because in that...
  5. M

    Engineering Fluid Mechanics book that's pure integration/vector calculus

    Hello. The textbook that was assigned to my class is not a good fit for my professor. The textbook simplifies the basic force equations so that there are no general equations with integrals or vector calculus calculations. Can anybody recommend a Fluid Mechanics book or books that deal only...
  6. Jianphys17

    Better textbook for analytical mechanics

    Hi at all. According to you which of the two texts, between Landau-Lifshitz (mechanics) and the Goldberg (classical mech) is better for study Analytical Mech ? Or there are other better ones ?
  7. G

    Mechanics of Materials -- inclined ladder

    Homework Statement [/B] The inclined ladder AB supports a house painter (85 kg) at C and the self weight (q = 40 N/m) of the ladder itself. Each ladder rail (tr = 4 mm) is supported by a shoe (ts = 5 mm) which is attached to the ladder rail by a bolt of diameter dp =8 mm. 1) Find support...
  8. Epoch

    Calculating Reaction Forces on Cylinders Resting on an L Profile

    Homework Statement Two cylinders, each with a mass of 10kg, are lying on an L profile. Neglect the thickness and weight of the L profile. Calculate the reaction force in b and e. Homework Equations G = mg The Attempt at a Solution So I tried to make a free body diagram of the cylinders. I...
  9. Alexander350

    Significant figures in a results table

    Homework Statement Basically there is a results table for the time taken for 20 oscillations. Three examples are 9.90, 11.16 and 12.68. I need to work out the time period to the correct number of significant figures. Homework EquationsThe Attempt at a Solution I divide by 20 to get the time...
  10. W

    QM: Infinite Potential Well

    Homework Statement I have a few questions I'd like to ask about this example. (C1 was already derived before the second part) 1. What does the line "The rest of the coefficients make up the difference" actually mean? 2. What does "As one might expect...because of the admixture of the...
  11. X

    2 unknown Forces+known resultant force

    Homework Statement Hi, I'm having trouble with my first mechanics assignment and I'd appreciate some help. So, an object is being pulled using two ropes (Fa and Fb) with a resultant force of 970 N along the x axis. The angle from Fa to the axis is 20 degrees, angle from fb to the axis is 51...
  12. X

    Calculating Unknown Forces in a Vector Diagram

    Homework Statement Hi, I'm having trouble with my first mechanics assignment and I'd appreciate some help. So, an object is being pulled using two ropes (Fa and Fb) with a resultant force of 970 N along the x axis. Angle from Fa to the axis is 20 degrees, angle from fb to the axis is 51...
  13. C

    Quantum mechanics transitions in an electromagnetic field

    Homework Statement This is problem (7.1) from John A. Peacock "Cosmological Physics". Show that the first-order perturbation term for quantum mechanics with an electromagnetic field, ##(e/m) \mathbf{A \cdot p}## is proportional to the electric dipole moment. What is the interpretation of the...
  14. S

    I Applying the Principle of Relativity to Quantum Mechanics

    I read the forum rules, I hope I am not breaking them as these principle is generally accepted and I am not contradicting mainstream science. "The principle of relativity, according to which the laws of physical phenomena should be the same, whether for an observer fixed, or for an observer...
  15. W

    Quantum Mechanics: Expectation values (Griffiths)

    Homework Statement A few questions: Q1) How does 1.29 flow to 1.30 and 1.31? How was the integral-by-parts done? Q2) The author states that <v> = d<x>/dt represents the expectation value of velocity. What does this actually mean? I tried to rationalise that d<x>/dt represented the velocity...
  16. F

    Important formulas in college mechanics?

    what are the most important formulas in calculus based mechanics? maybe formulas that you are almost certain will be on one of the few tests given during the semester? I am asking because I am self studying right now before class starts and there seems to be A LOT of formulas. so I was wondering...
  17. Demystifier

    Insights How I Stopped Worrying and Learned to Love Orthodox Quantum Mechanics - Comments

    Demystifier submitted a new PF Insights post How I Stopped Worrying and Learned to Love Orthodox Quantum Mechanics Continue reading the Original PF Insights Post.
  18. mastermechanic

    Mechanics of Materials segment choosing

    Homework Statement Homework Equations Torque = F. d Distributed Force -> Concentrated Force = w.d The Attempt at a Solution Concentrated force is equal to 40kN and I have found the B(y) as -10kN by taking moment with respect to the A point. And from the equilibrium A(y) is 50 kN...
  19. T

    I New book on the foundations of quantum mechanics

    Some years ago now, I was a regular reader and poster here and had a lot of fun arguing about the meaning of Bell's theorem, the relative merits of different "interpretations" of QM, etc. I just popped in for the first time in a long time, and it is nice to see some familiar faces (and many new...
  20. Alexander350

    B Where does this equation for stationary points come from?

    In the Classical Mechanics volume of The Theoretical Minimum, he writes a shorthand equation for a small change in a function. Please could someone explain exactly what it means and where it comes from?
  21. P

    Quantum Quantum Mechanics Textbook，Zettili vs Shankar

    Hello Everyone, I am an undergraduate physics student who planned to study quantum mechanics. I have been reading the introductory book by Griffiths, however I found that his book seldom uses Dirac Notation and there is little about mathematical formalism on quantum mechanics. Therefore I would...
  22. M

    I Compatibility of Quantum Mechanics and Special Relativity

    Hello, In my free time, I've been learning about an eclectic range of topics (ie. French History, Kinetic Theory etc.). Most recently I've been focused on Quantum Mechanics, which happens to be most complex topic I've ever looked at. Typically I write up summaries after reading from various...
  23. T

    I Relativistic Quantum Mechanics vs Quantum Field Theory

    What's the difference between relativistic quantum mechanics and quantum field theory? In principle, my guess is that to do the former, one needs to express the Hamiltonian in a relativistic, Lorentz invariant, form, because it seems to be the only frame-related term in the wave equation. (Is...
  24. D

    Constants of motion in quantum mechanics

    Homework Statement A particle of mass m and spin s, it's subject at next central potential: ## \begin{equation*} V(\mathbf{r})= \begin{cases} 0\text{ r<a}\\ V_0\text{ a<r<b}\\ 0\text{ r>b} \end{cases} \end{equation*} ## Find the constants of motion of the system and the set of...
  25. A

    How Calculate Coriolis aceleration from Christoffel Symbols?

    Homework Statement Hi, We are trying to calculate the Coriolis acceleration from the Cristoffel symbols in spherical coordinates for the flat space. I think this problem is interesting because, maybe it's a good way if we want to do the calculations with a computer. We start whit the...
  26. K

    Dynamics of a point mass in circular motion

    Homework Statement Dear All, I'm having a hard time solving the following problem: A point of mass is moving on a circular plane (Oxy), where the circle's formula is: The force acting on mass "m" is defined as: We're looking for velocity of point "m" in position (1,1) =V1, and in position...
  27. senatorarmstrong

    Courses Preparing for Classical Mechanics: Tips for Success

    Hello PF, I am taking classical mechanics this fall and I am horrified. I am just not sure if I have the mathematics background for the class. I am still finishing differential equations (about half way done) and I am almost done with calculus 3. The pre-requisite for the class is DE...
  28. mertcan

    Large deformation in solid mechanics

    Hi initially I am aware that large deformation in solid mechanics requires non linear strain theory in the lieu of infinitesmall strain theory. But I wonder that if we can approximate large deformation of material using infinitesmall strain of small elements employing and summing linear strains...
  29. navierstokes

    Courses Aerodynamics and flight mechanics for control engineering

    I have a huge interest in aviation and aerodynamics, despite being an EE student. I took Fluid Mechanics courses as electives, and I'm learning some aerodynamics on my own. I was thinking if there is any field of work where the knowledge of both an EE and aerodynamics/flight mechanics would be...
  30. B

    Very difficult mechanics problem with friction

    Homework Statement A hollow cylinder with mass m and radius R stands on a horizontal surface with its smooth flat end in contact the surface everywhere. A thread has been wound around it and its free end is pulled with velocity v in parallel to the thread. Find the speed of the cylinder...
  31. W

    Quantum Mechanics: Outside a (in)Finite Well

    Homework Statement Referencing image attached. I'm not sure how the example arrived at ψ ⇒ 0 at x<0 and >L as K ⇒ ∞ in the limiting case of an infinite potential well. Homework EquationsThe Attempt at a Solution I tried simply applying limits to the wavefuction but in the case x<0, the...
  32. L

    How to derive the slip angle for a trailer-car system?

    I just watched this video that perfectly explains how to derive the equations for the slip angle of a car: However, how could this be done for a three axle system (car-trailer)? Would you have to express distance a (in the video) in terms of b (distance from centre of gravity to the second...
  33. C

    Determining Acceleration of Hinge in a Beam and Hinge Structure

    Homework Statement The following structure,A force F is applied to the right hinge.If the mass of the rods are equal ,and the length of the rod is equal,the intial angle is also equal to 90 degrees (a square),What is the intial acceleration of leftmost hinge ? Homework Equations Coordinate...
  34. R

    Engineering Research in Fluid Mechanics for MS

    Hi Everyone, I am currently doing undergraduate program in mechanical engineering. I want to pursue masters after my B.Tech in the field of fluid mechanics and aerospace engineering.I want to know about the prospects of this field in the future research. Thanks in advance, Ritwik Kulkarni
  35. E

    Classical Mechanics, MIT 8.01 -- Useful learning resource?

    Hello all. This is my first post. I am very passionate with physics even if i did not study them at university. I studied administation and another degree in economics and politics. However, i love physics so much and i decided to learn more about this subject. So, i searched MIT's undegraduate...
  36. C

    Is my Rolling Body Mechanics Solution Correct?

    Homework Statement In the picture ,problem 8.29 Homework Equations Energy conservation ,velocity relation ,momentum The Attempt at a Solution First i defined the speed of the body relative to the ground as Vb and speed of plane relative to the ground as Vp. From momentum ,VbcosΘ=-Vp .From the...
  37. C

    Why don't we feel the Earth's rotation?

    Pardon me if this seems like an incredibly naive question. Perhaps the question could also be rephrased as such: "Why do the laws of classical mechanics hold true with Earth as a frame of reference?" A quick google search turned up the usual answer: the Earth rotates at a constant speed...
  38. R

    Studying Requirement for Goldstein level Classic mechanics

    GreetingsTo be straight, I've been studying Goldstein Classic mechanics.While studying, it turned out that this is not a book for my level,(knew it would be challenging, but even far beyond)but even after finding out that something is wrong, i kept studying this book, by doing some research or...
  39. ramzerimar

    Courses Is CFD fluid mechanics + computer science?

    I'm having fluid dynamics classes right now and I'm enjoying it very much (much more than my solid mechanics classes, by the way). Also, I do like programming and computer science, and CFD looks like a very interesting field. I'm developing a real interest for it. One question for those who are...
  40. MattRob

    Flight Mechanics - Maximum Cruise Altitude

    So, I was helping someone with some science fiction stuff and got to poking into flight mechanics. So we've got a balance of lift and weight, and drag and thrust. The speed at which thrust and drag cancel determines the speed of flight. The speed of flight determines lift, and lift must cancel...
  41. Alexander350

    Finding all the forces in this system

    Homework Statement [/B] I am trying to identify every force in this system and prove that it is in mechanical equilibrium when tan(θ)=⅓. Initially I had to solve it by finding when the derivative of potential with respect to θ was 0, but now I am just trying to resolve the forces. Homework...
  42. M

    Courses Mechanics / E&M / Multivariable Calc / Diff EQ Self Study

    Hello Physics Forums! I'm in a little bit of an interesting situation. I've completed the classes offered at my school, but have been told that if I can directed-study these four courses they will provide me with a credit bearing exam for college undergraduate credit. Do you have any...
  43. person123

    Is my intuition about torque and acceleration incorrect in this scenario?

    Suppose there are two discs held in contact such that they rotate around the same axis of rotation. A torque is applied to one of the discs, and due to friction the other disc accelerates. Using calculus I found the torque applied due to friction for a disc to be ##\frac {2μF_N r} {3}##, meaning...
  44. C

    I How do we interpret an EM wave using Quantum Mechanics?

    I know that if the intensity of a light beam with of a certain frequency varies it means the number of photons the light beam is composed of varies and not the individual photons energy. That would mean the E and B field amplitudes vary. This would mean that that the amplitudes of the E and B...
  45. T

    Special Relativity - Rocket problem (particle mechanics)

    Problem statement: A rocket propels itself rectilinearly by giving portions of its mass a constant (backward) velocity ## u ## relative to its instantaneous rest frame. It continues to do so until it attains a velocity ## v ## relative to its initial rest frame. Prove that the ratio of the...
  46. R

    Calculating Projectile Force from Rotational Velocity of a Throwing Sling

    Hey, I am not sure if this should be posted somewhere else, if so if you could direct me it would be much appreciated. So my question is how would i find the rotational velocity of a sling and how i could use that to calculate the force of a projectile from said sling. I've tried doing some...
  47. C

    Difficulty with Mathematical Methods of Classical Mechanics

    Homework Statement A friend and I are going through Vladimir Arnold's Mathematical Methods of Classical Mechanics, but I think my lack of a background in pure math / proofs is seriously hampering my ability to do any of the problems in the first chapter. For example: PROBLEM. Show that if a...
  48. RJLiberator

    Quantum Difference between these two Griffiths Quantum Mechanics books

    1. Amazon link: https://www.amazon.com/dp/0131118927/?tag=pfamazon01-20 ISBN: 978-0131118928 This is the book that my class syllabus suggests based off ISBN number, however it is $119.00 to buy off Amazon. 2. Amazon Link: https://www.amazon.com/dp/1107179866/?tag=pfamazon01-20 ISBN...
  49. E

    Phase Difference in Parallel SHM with Equal Amplitude and Frequency

    Homework Statement Two particles move parallel to the x-axis about the origin with the same amplitude and frequency. At a certain instant, they are found at a distance A/3 from the origin, on opposite sides of the origin, with their velocities in the same direction. Find the phase difference...
Back
Top