Mechanics Definition and 999 Threads

I am not a teacher, but I have made an interesting observation regarding classical mechanics education. It is surprisingly common that even students at academic level do not seem to fully understand Newton's third law (action and reaction) and confuse it with Newton's second law...

Homework Statement I have to find axial force at X for the following structure: https://i.imgur.com/8o01fkC.jpg The Attempt at a Solution These are my workings https://imgur.com/JfSfk9Z https://imgur.com/3HuDN4d I didn't work out moments because the question only asks for axial force, is...

Homework Statement The given system is released from rest. Assuming no friction, mass-less pulleys and ideal strings; calculate the accelerations of the pulleys. Homework Equations Constraint equations. F=ma The Attempt at a Solution Taking the above assumptions; And applying constraints...

I’m a bit confused about what exactly lagranigian mechanics is. I know that L = Ke - Pe I also know the equation d/dt(∂L/∂x’) - ∂L/∂x = 0 1.) Apparentaly solving this equation gives the equations of motion. What exactly does that mean though? I solved a very simple problem and got the...

Homework Statement A student throws a stick of length l up in the air .At the moment the stick leaves his hand ,the speed of the stick's end is zero.The stick completes N turns just as it is caught by the student at the initial release point . Show that the height to which the centre of mass...

Homework Statement Homework EquationsThe Attempt at a Solution I have done part a, I have no idea on part b, here is my attempt,

I tried using the Bernoulli equation to solve this. I took two points at the surface of the water in both the containers and formed this equation: gh_{b}=\frac{1}{2}v^2+gh This is assuming that the velocity of the water in the large tank is approximately zero and using the fact that both the...

Homework Statement The object is made out of multiple parts. The inertia matrices of every part are given. Only one part is rotating. How do I find the total inertia matrix. Homework EquationsThe Attempt at a Solution I thought that I could sum the inertia matrices, after tranforming them to...

I have no prior experience in physics, but I am a math undergrad so I know calculus, differential equations, linear algebra and stuff like that. So I'm ready to move from the conceptual "bedtime story physics" to stuff with real mathematical rigor. So, what is classical mechanics all about...

If you had two masses, m_{1} and m_{2}, and you released them in space infinitely far apart, their kinetic energies would satisfy \frac{1}{2}m_{1}v_{1}^2+\frac{1}{2}m_{2}v_{2}^2=\frac{Gm_{1}m_{2}}{r} if they met with a distance r between their centres of mass. This equation therefore tells you...

i want an article or video that i can start with at the journy of understanding the basics of quantum physics and quantum mechanics i don't want a book because in my country i would not find this types of books every where it's unique to find them thanks

I'm looking for a source of harder mechanics problems, preferably with solutions. I'm supposed to use the Young and Freedman book, but I find it rather teadious and superficial; most problems don't match the difficulty and depth of the ones on the exam. I had my mid-term tests recently, and got...

Homework Statement I am currently solving a problem and I am not sure if it is correct. There are two particles A and B. A has a constant velocity with |\vec{v}| = 3 and starts from y = 30 B has constant acceleration with |\vec{a}| = 0,4 The goal is to find the angle between the...

Can anyone refer to some good book on Non-Equilibrium Statistical Mechanics? The book should contain the basics, and can go up to any advanced level. Any level of math is acceptable.

Homework Statement An object is released from rest in the gravitational field of the Earth. Air resistance is negligible. How far does the object move during the fourth second of its motion? A. 15 m B. 25 m C. 35 m D. 45 m Homework Equations v = u + at s = ut + 1/2 at^2 v^2=u^+2as...

The particles are moving under force F = rK when r = 1/u and u = 1/r I tried to solve the problem by defining a variable v = u4 and u = v1/2 But I can not divide variable v out of variable u I want to find r (Radius) of orbit

What books include the theory of lagrangian mechanics? And where can i also find some problems?Could lagrangian mechanics help me in solving problems with oscillations?

I came to know that time evolution in classical mechanics is highly non linear. Is there any case that it become linear?

I have a few issues with understanding a section of Griffiths QM regarding Hermitian Operators and would greatly appreciate some help. It was first stated that, ##\langle Q \rangle = \int \Psi ^* \hat{Q} \Psi dx = \langle \Psi | \hat{Q} \Psi \rangle## and because expectation values are real...

<Moderator's note: Moved from a technical forum and thus no template.> We place a ball on an an inclined plane (angle ##\theta##). At the top of the ball is a small dog who always stays at the top over the course of the ball's movement. What is the motion of the ball? ------------------ I...

Hi, i know that The homogeneity of space and time implies that the Lagrangian cannot contain explicitly either the radius vector r of the particle or the time t, i.e. L must be a function of v only but the lagrangian definition is ##L=\int L(\dot q,q,t)##, so velocity appears in the definition...

Homework Statement A block is placed inside a horizontal hollow cylinder. The cylinder is rotating with constant angular speed one revolution per second about its axis. The angular position of the block at which it begins to slide is 30° below the horizontal level passing through the center...

I get how to find vertical and horizontal forces on a submerged surface (vertical = weight of fluid and horizontal = force on vertical projection). I also get how to find the point of application for the horizontal force using a moment balance. But how do you determine the point of application...

Homework Statement Homework EquationsThe Attempt at a Solution This is the Solution. I am having trouble understanding parts of it. The first part I don't get is why the e^i... goes with the -z. Did my professor just choose one at random, or is there a specific reason? The second part...

Homework Statement I am trying to understand a solution to a problem. I may not need to post the entire question, I just need to know if ##-i = e^{\frac{-i*pi}{2}}## Homework EquationsThe Attempt at a Solution the reason for this question is that one step of the problem has a quantity...

Could you, please, give me reference to any paper or talk by Paul Dirac where he expresses his views about or give comments to the de Broglie-Bohm theory (Bohmian mechanics)?

Homework Statement Homework Equations G = Shear Stress/Shear Strain G = E/(2(1+n)) n being poissons ratio The Attempt at a Solution So I know the easiest way to solve is simply to manipulate the first equation a little bit >>> Shear Stress = G * Shear Strain >>> Shear Stress = P/A >>>> P...

What is a symplectic manifold or symplectic geometry? (In intuitive terms please) I have a vague understanding that it involves some metric that assigns an area to a position and conjugate momentum that happens to be preserved. What is 'special' about Hamilton's formulation that makes it more...

Homework Statement There are two particles. There are moving equally on two intersecting lines to intersection. On time t=0 is the distance of two particles d. The velocity of one particle relative to the other has a projection u in the direcion of d. In direction perpendicular to d is the...

Hello everyone. I have this problem: 1. The problem statement, all variables and given/known d I throw stone from height h at an angle α, then at an angle β (so I know h, α, β). I throw it with same velocity v. The stones fall in same distance d. The question is: find the d (distance) and v...

Homework Statement I am not looking for a solution to the problem, as much as I need a clarification on what it's asking for. The problem: "A particle of mass m slides down an inclined plane under the influence of gravity. The particle is starting its motion from rest. Find the time dependence...

Why can we calculate factor of safety using Strain (fail)/ Strain (allow) only if the load applied is linearly related to the stress developed within the member? What happens if the two are not related? Also, my textbook says factor of safety can also be calculated by stress (fail)/ stress...

Homework Statement Need to find the acceleration of the blocks, all surfaces are smooth : https://drive.google.com/file/d/0B5bF4yPQOejoazhWeEgySmtfSnc/view?usp=drivesdk Homework Statement Need to find the acceleration of the blocks Homework Equations a1 + a2 + a3 =0 (acceleration of strings...

Hello, I was referring to this thread: https://www.physicsforums.com/threads/accelerating-atwoods-machine-problem.44305/ to solve a problem on accelerating atwood machines in which, naturally, one attempts to find the acceleration of each of the individual masses. Although I now understand how...

Homework Statement This is the problem verbatim: The Potential energy of a one-dimensional mass m at distance r from the origin is U(r) = U0 ((r/R) +(lambda^2 (R/r)) for 0 < r < infinity, with U0 , R, and lambda all positive constants. Find the equilibrium position r0. Let x be the...

I'm sophomore in physics looking for best free books for classical mechanics and for vibrations and waves. Anyone with references pleaseThank you

Hi. From what I read, according to Quantum mechanics "even though it looks like objects are in definite places, when we get down to ridiculously tiny objects (like electrons) they seem to be not he in anyone place. And everything looks like a hazy clouds of probability."...

Homework Statement A state of a particle in the potential box of width a with infinitely high walls is described by the wave function: Ψ(x)=Ax(x-a) Find the probability distribution of various value of particle energy, mean value and mean square fluctuation of energy. Homework Equations...

Homework Statement Hi There, I'm having trouble understanding (what I guess should be) a simple concept and so I can't apply it to a project I'm working on (also kind of rusty on torques and mechanics problems) If I have a hinged beam (of uniform weight) and I lift it from one end and stay...

Hello, first of sorry for asking what maybe a stupid question. I am teaching myself physics by watching lessons about QM, Classical Mechanics, EMT etc. I was watching Susskind's lectures about statistical mechanics lately and he derived equation of energy E= 3/2 x k x T. 3 in 3/2 came from...

Hey there, there may be many threads about this problem, but I would want you to recommend me few books to read about mechanics from the bottom to the top. I mean, I don't have that much of a problem in calculus, but I'm not excellent in it either. So I would want a good textbook or bunch of...

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...

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.

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?

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...

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...

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 ?

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...

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...