Mechanics Definition and 999 Threads

I think Weinberg is quite clear about this: On p.87 of the second edition of his quantum mechanics book, he says, and on p.88: After having discussed decoherence, he says on p.92: For the instrumentalist approach (apparently your view of the matter), he states on p.92f this drawback: Then...

What are the best theoretical books I can study for understanding the basic as well as advanced; mass, energy and quantum mechanics.

I know that this is the general case of the Einstein and Debye Model.

Hi. In an Elitzur–Vaidman bomb tester, will the guiding wave be different in a situation with a live bomb compared to one with only a dud? And if yes, how does the bomb interact with the guiding wave? Because usually it is described as a pointlike device that only explodes when hit by the...

I copy again the statement here: So, I think I solved parts a to c but I don't get part d. I couldn't even start it because I don't understand how to set the problem. I think it refers to some kind of motion like this one in the picture, so I'll have a maximum and a minimum r, and I can get...

In quantum mechanics, we have the partition function Z[j] = e-W[j] = ∫ eiS+ jiOi. The propagator between two points 1 and 2 can be calculated as ## \frac{\delta}{\delta j_1}\frac{\delta}{\delta j_2} Z = \langle O_1 O_2 \rangle## The S in the path integral has been replaced by S → S + jiOi...

The landing speed of an airplane is 360 kph. When it touches down, it puts on its brakes and reverses its engines. The retardation in its speed is 0.2 times the square root of its speed. Determine the time elapsed in seconds from the point of touchdown until the plane comes to a complete stop.

A car starting from rest picks up at a uniform rate and passes three electric post in succession. The post are spaced 360 m apart along a straight rod. The car takes 10 seconds to travel from the first post to the 2nd post and tales 6 seconds to go from the 2nd post to the 3rd post. Determine...

The depth of the crater of the Taal volcano was calculated in the following manner: From a helicopter flying vertically upward at 6m/s. A small bomb was released at the instant the helicopter was 20m above the crater surface. The sound of explosion was heard 9sec later. If the speed of sound is...

I recently read @Demystifier's paper entitled, Bohmian Mechanics for Instrumentalists and I found it quite interesting. There is a danger that I am guilty of a certain amount of confirmation bias, as I find that deterministic interpretations are more closely aligned to my own logical reasoning...

Hey, applied maths and physics student here. I started wondering recently what the meaning of measurement was in quantum mechanics, and I remembered that I had once heard of the bohmian interpretation which challenged the impression I had so far (which was that hidden variables had been...

I'm interested in a book which treats scattering in quantum mechanics aimed at the research-level. I'm particularly interested in a text which focuses on mathematical details such as the analytic structure of the S matrix, the relation between the S matrix and various green's/two-point...

I figured out stokes law equation but I am unable to proceed further

Here is the picture on the system. I have to find the period (T). The masses, R and dX is given. The systam at first is at rest, then at t = 0 we pull the plank to dX distance from its originial position. In the thread...

The slope of the v^2 vs h graph is g

As a quarantine hobby I've been learning about Grete Hermann and the early history of QM. I find her early philisophical contribution to be interesting, but I lack the background to put it into a modern context. A brief description can be found in the arxiv paper: Grete Hermann: An early...

In order to compute de lagrangian in spherical coordinates, one usually writes the following expression for the kinetic energy: $$T = \dfrac{1}{2} m ( \dot{r}^2 + r^2 \dot{\theta}^2 + r^2 \sin^2 \theta \dot{\phi}^2 )\ ,$$ where ##\theta## is the colatitud or polar angle and ##\phi## is the...

Hi! I need help with this problem. m1-2-3-4 and R are given. There is no slip in the system. I have to give F1-2-3-4 in respect of the masses and R. Here is what I managed to m1 is easy: m1*a = m1*g - T(tension of the rope) m2: m2*a = T - (?) <-- I have a problem with this. F1 and F3 is the...

Homework Statement:: ... Relevant Equations:: . What is the minimum mathematic requirement to the Lagrangian and hamiltonian mechanics? Maybe calc 3 and linear algebra?

I found out the time when rotation ceases to be 4 ##v_0## /5*mew*g, where mew=coefficent of friction of surface but I am unable to plot the graph post that time

This isn't really a proper homework question, but something I wondered about myself. To simplify things, we say that pivot point is in the origin of a Cartesian coordinate system, and the angles are constrained to the first quadrant. We see that the weight of the barbell is given as $$F =...

Hi- So I have been studying physics for a long time, and I love most parts of it, but I have a love-hate relationship with classical mechanics. Every time I read my textbook I can work my way through it and it makes sense to me, but one or two days later I forget all the formulas I have...

A body is placed on a surface with friction Force is applied to the right at the upper end of the body What is the condition that will cause the body to roll over?

I can not solve this problem: However, I have a similar problem with proper solution: Can you please guide me to solve my question? I am not being able to relate Y R (from first question) and U (from second question), and solve the question at the top above...

This is a general property of eigenvectors of Hermitian operators. State functions are a particular class of vector, and it is easiest to work in the general formalism (I am hoping to show how ket notation makes qm easier, not just do standard bookwork at this level). Suppose O is a Hermitian...

I tried doing it a few times and this is all I get: c(˙f1+˙f2)=a˙a2+a2˙a−3ca2+˙ha2+2ha+2˙af′2+2a˙f′2c(f1˙+f2˙)=aa˙2+a2a˙−3ca2+h˙a2+2ha+2a˙f2′+2af2′˙ Please let me know where I'm going wrong. Thanks

I understand how they might have got to these answers but I'm still kind of shaky on how the mass of the rope plays a role in the tension at point B, and how to mathematically represent the tension at any point along the rope; I know the tension varies because the rope has mass. If I was to...

Summary:: I'm solving an exercise. I have the following center of gravity problem: Having the function Y(x)=96,4*x(100-x) cm, where X is the horizontal axis and Y is the vertical axis, ranged between the interval (0, 93,7) cm. Determine: a) Area bounded by this function, axis X and the line...

"Collection of Problems of Mechanics" by Meshcherskii.I see how the answer could be arrived at because each successive drag increases the number of ropes that must be used, but what I don't understand is why the thrust and drag of the tug doesn't play a role in the number of ropes required.

In the following cross section, the static guide plate (light blue) is rigidly constrained, fixed to the body (not shown) of the mechanism. It serves as the mounting point for a cranked axle (dark blue) via a combination thrust and radial bearing (pink & yellow) that constrains it to a single...

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A reservoir supply tunnel transfers water from a high level storage reservoir via a 200mm diameter pipe to a lower intermediate reservoir. The total height difference between the free surfaces of each reservoir is 76 m. The pipe is 700 m long and the coefficient of friction, Cf is 0.009. The...

A relativistic origin of QM is proposed in https://iopscience.iop.org/article/10.1088/1367-2630/ab76f7 It is proposed that lorentz transformation that include superluminal observers (whether those observers exist or not) explain the indeterministic behavior of QM. Not only that, it also would...

But yet again my text says that option 4 is correct.

Initial velocity u=0 Let Final velocity be v Then, KE acquired by the object=1/2mv² So the answer must be option1 i.e. m¹ But my textbook says the answer is- m to the power zero.Please explain this discrepancy.

I'm often got confused about why the direction of pseudo force is taken opposite to the direction of motion of the body. As specific, I have this question. In this, I didn't understood about why the direction of pseudo force is taken in right, in the diagram of solution provided to this...

I need help .I did not A) E < V0 for T =? (passing coefficient ) B) E = V0 for T = ? C ) E > V0 for T =? A

Hi, I am trying to figure out the strength of the various type of airflow for my Venturi ejector device. Please refer to my diagram that illustrates scenario A or scenario B. The SAME amount of compressed air is injected for both scenario A and B. For simplicity, I have added to an electrical...

In quantum mechanics in books authors discuss only cases ##E<V_0## and ##E>V_0##, where ##E## is energy of the particle and ##V_0## is height of the barrier. Why not ##E=V_0##? In that case for ##x<0## \psi_1(x)=Ae^{ikx}+Be^{-ikx} and for ##x\geq 0## \psi_2(x)=Cx+D and then from...

In R Shankar text on “principles of quantum mechanics’ discussing the adjoint operation, 1.3.8 shows that a|V> => <V|a*. Then 1.3.9 then states that <aV| = <V|a*. Is this a typo error?

Recently I started wondering why there seems to be so few practical/engineering applications where you need to calculate the momentum of something. I must emphasize that I don't mean usage of the concept of momentum or the law of conservation of momentum, but the value of the quantity itself...

(So this is the system given) The following is my analysis: (i) (ii) Well, my problem is - I got a negative acceleration and its quite impossible to have block B moving to the left. So I am wondering if there are any mistakes I've made.

How do "sinϕ - cosϕ sinϕ" become 0 ?

First I found partition functions of both the systems and hence total energies of them using above formulas. Z(A) = (1 - e-ε/kT)-1 and Z(B) = (1 + e-ε/kT) Then I equated these values to the given values of total energies. I got: For System A, T(A) = ε/kln(2) > 0 For System B, T(B) =...

Summary:: I have solved the question but I'm getting answers wrong, some reaction equations seems to have trouble. Question: Let m1 = 1 kg, m2 = 2 kg and m3 = 3 kg in figure. Find the accelerations of m1, m2 and m3. The string from the upper pulley to m1 is 20 cm when the system is released...

Upto now I've only dealt with the problems regarding non - degenerate energy states. Since bosons do not follow Pauli's Exclusion Principle, three bosons can be filled in two energy states (say E1 and E2) as: E1 E2 1 boson 2 bosons 2 bosons 1 boson 3 bosons 0 bosons 0 bosons 3...

Is Hamiltonian mechanics a mathematical generalization of Newtonian mechanics or is it explaining some fundamental relationship that has a meaning that extends into our nature ? I guess my question is what would led William Rowan Hamilton to come up with his type of mechanics or anything...

Regarding the first part, I proceeded as: nx ny nz 4 0 0 => E1 = 16C 0 4 0 => E2 = 16C 0 0 4 => E3 = 16C 3 1 0 => E4 = 10C 3 0 1 => E5 = 10C 0 3 1 => E6 = 10C 1 3 0 => E7 = 10C 0 1 3 => E8 = 10C 1...

I am working on a project where I have to calculate various results relating to the motion of a water bottle rocket being launched. I am currently stuck on trying to find how long the thrust period of the rocket is. The model for the rocket is as follows: It is a 2L (0.002m3 bottle filled with...