Mechanics Definition and 999 Threads

Homework Statement A ladder of length 5 m is resting against a SMOOTH wall, its point of contact being just below a first floor window. The bottom of the ladder rests on the ground and the coefficient of friction between the ladder and the ground is 0.28 A person of mass 78 kg climbs the...

It is the resolution given by my thermal interpretation, and this resolution is valid (independent of the thermal interpretation) even without being accepted. Bell assumes that measurement outcomes follow strictly and with infinite precision Born's rule for a von Neumann measurement. But the...

I am not sure whether this is posted before but it looks really good to me. http://www.tcm.phy.cam.ac.uk/~bds10/aqp.html

Homework Statement Fast moving α particles of mass m make collisions in a cloud chamber with gas atoms of mass M and negligible initial velocity. After a collision, the velocities of the scattered α particles and the recoiling gas atoms are v and V respectively, the former being inclined at an...

Homework Statement A 1500 kg car is traveling at a speed of 30.0 m s-1 when the driver slams on the brakes and skids to a halt. Determine the stopping distance if the car is traveling down a 10o slope. The coefficient of kinetic friction between the car and the road is 0.80. Homework Equations...

Hi all, I recently learned the concept of Maxwell's speed distribution and became interested in how to use similar momentum distributions to study the probabilistic motion of a classical free particle. I have done some of my own reading on probabilities and distributions (no formal lessons yet)...

Greg Bernhardt submitted a new PF Insights post The Fundamental Difference in Interpretations of Quantum Mechanics Continue reading the Original PF Insights Post.

Greg Bernhardt submitted a new PF Insights post Statistical Mechanics Part I: Equilibrium Systems Continue reading the Original PF Insights Post.

Homework Statement If the velocity v of the air in a boundary layer having a dynamic viscosity of 18x10-6 kg/ms is given in terms of the distance y from the surface by v = ay + by2 where a and b are constants, calculate the surface shear stress if at 1.5 mm from the surface the velocity is 75...

I am self studying Classical Mechanics and I am a bit confused about this. After reading Kleppner Kolenkow Mechanics can I read Symon's Mechanics or do I need to read anything in between like Fowels or Marion&Thornton? I already studied the Maths portion upto Multivariable Calculus,Real...

I need a book with exercises, to try to excel my next classical mechanics, I really to get a good grade. Thank you very much!

I’m felling demotivated because I had a bad grade, I don’t know how I got such kind of grade. However, I’m looking to get a very good grade in the next test, that will count 100%. I’m in the first year of physics, what advices do you have on how to study(CM), which exercises? What books should...

Hi all, Is there a critical analysis of this work ( https://arxiv.org/abs/1506.00431 ) that claims to develop a new representation of microstate and then using this representation as a reference-and-imbedding-structure, to develop a new foundations of an intelligible reconstruction of the...

Homework Statement Homework EquationsThe Attempt at a Solution The option (a) says that the 1st coin remains at its earlier position. Due to gravitational force, the 1st coin falls down, hence option (a) is wrong. I don’t understand the difference between option (B) and (C). In my opinion...

Homework Statement Referring to the attached diagram, the object ABCD is kept in an isolated system where it is under no external influence of any kind. A· An instantaneous force F acts along the edge BC of the block ABCD, where M is its mass, with its center of mass located at O...

Homework Statement Homework EquationsThe Attempt at a Solution ## E \propto n^2 ## ## \frac { \Delta E} E = \frac { 2n +1} {n^2} ## In the limit of large quantum number, ## \frac { \Delta E} E = \frac { 2} {n} ##, option (a).

I would be in college in 2019 (currently I'm in standard 11). I'm greatly interested in Quantum mechanics, QFT, QCD and Quantum Geometerodynamics. Of these, I want to do an internship on the first, because I don't think I'll be able to touch the others till the 2nd year in college. I'm living...

Homework Statement Homework Equations This is solution of Griffith problem 11.16 The Attempt at a Solution This is procedure to get a 1-D integral form of Schrodinger equation. I don't understand why that contour integral include only one pole for each contour?

Homework Statement Homework Equations I consider four directions from the point of throwing the balls, east, west, up, down. At any given time, the balls will be at different distance from this point, (the upward ball will travel less distance than the downward ball). So, it could not be a...

Homework Statement Homework EquationsThe Attempt at a Solution I think : the question means that almost all of the potential energy gets used into the explosion. If this is true then the potential energy gets reduced by ## \frac { GM^2} R ## or if the star just gets transformed into a...

Homework Statement Homework EquationsThe Attempt at a Solution total kinetic energy of a rigid body = rotational kinetic energy of the body around its center of mass + translational kinetic energy of center of mass For solid cylinder, total kinetic energy = ## \frac { [I = \frac 1 2...

Homework Statement Homework Equations [/B] apparently noneThe Attempt at a Solution [/B] Hi, this is a question from the OCR for self studying purposes. Only the first question is relevant for me. I know that the solution is 120N in the opposite direction to the weight, but i can't get to...

is there a way for me see EVERY solution from goldstein's book? i already have some solutions, but not every one

Homework Statement One end of a light elastic string of stiffness mg/l and natural length l is attached to a point O. A small bead of mass m is fixed to the free end of the string. The bead is held at O and then released so that it will fall vertically. In terms of find the greatest depth to...

Homework Statement Homework EquationsThe Attempt at a Solution Let's say that the last carriage gets uncoupled at time t = 0s and at this time the train has moved a distance ##l_0##.The resistive force could be given as ## F_r = AM##, where A is the appropriate constant and M is the mass of...

Homework Statement Find relation between real normalisation constants ##B_1## and ##B_2## for the following wavefunction, $$ \Psi_k =\sum_{k=1,2} \frac{B_k}{\sqrt{4\sigma ^2 + 2it}} \exp (ip_k (x - \frac{p_k}{2}t) - \frac{(x - p_k t)^2}{4\sigma ^2 + 2it}) $$ The working is rather long so...

For my final semester exam, where building paper roller-coaster with marbles as the coaster and one of the things were testing is ride duration. The group with the longest run time will get extra credit and my GPA could really use the boost. so i guess my question is what's the best way to...

Hi, I've been studying fluid mechanics for my mech. engineering degree for the past few months. Unlike my other subjects (mechanical analysis, thermodynamics, automated systems, mechanical vibrations), I can't seem to grasp the problem-solving technique. The annoying thing is, I find the...

Hi, I was studying for my final exam on statistical physics and a doubt raised on my head that was truly strong and disturbing (at least, for me), and that I couldn't answer to myself by now. The doubt is: Given that we have in d dimensions a fermion non interacting gas, the statistical...

Hi, in the following problem, I need to find the inertia of the system. The axis of rotation passes through the center of mass ( the pink dot). I understand that I will be equal to 4(mr^2). However, I do not understand why r= 3 (6 divided by 2) and not sqrt13 ( half of the diagonal of the...

In statistical mehcanics(pathria, 3rd edition), I have some questions for ideal fermi and bose gases. The textbook handles the approximation for z(=e^βµ) and nλ^3 (n=N/V, λ : thermal de Broglie wavelength). It considers the cases that z<<1, z~1, nλ^3~1,<<1,→0 and so on. In here, I am confused...

two saipens one known as Alpha who is on the left and the other on right Beta are present, Alpha first presses down on a bar and Beta has to use all of its strength to lift Alpha's hand a distance h a distance, in this scenario the fulcrum is placed close to Beta, now in the next scenario it is...

how is md^2r/dt^2 . dr/dt = d/dt (1/2 m (dr/dt)^2 ) Thank You

Homework Statement [/B] In this example, I know that I can define the horizontal contribution of kinetic energy to the ball as ##\frac{1}{2}m(\dot{x} + \dot{X})^2##. In the following example, Mass ##M_{x1}##'s horizontal contribution to KE is defined as ##\frac{1}{2}m(\dot{X} -...

If I have a general (not a plain wave) state $$|\psi\rangle$$, then in position space : $$\langle \psi|\psi\rangle = \int^{\infty}_{-\infty}\psi^*(x)\psi(x)dx$$ is the total probability (total absolute, assuming the wave function is normalized) So if the above is correct, does that mean...

Hi at all. I'm wondered is necessary learn well analytical mechanic ( eg learning The Goldstein's book), for understand and study QM ?

Probably a very simple question: Does the coefficient of restitution depend on the collision being performed? Consider two masses ##m_1## and ##m_2##. They are placed on a frictionless horizontal table and ##m_1## is given an initial velocity, collides 1-dimensionally with ##m_2##, and the...

Homework Statement There is a uniform rod of mass m = 1 kg and length L = 0.2 m fixed to the wall by an axis passing through its end. A uniform ball of mass M = 0.1 kg and radius R = 2.85 cm is on the ground, below the axis of the rod, such that the rod's unfixed end is at the height of the...

Hello, I am working on a project where I am trying to find the weight distribution on a 4 wheeled vehicle that is traveling diagonally up an incline. You can effectively think of the vehicle as having a pitch and a yaw angle in the body frame. Using an arbitrary location of the total center of...

and it is free (legal) Quantum Mechanics for Engineers by Dommelen

"... quantum mechanics isn’t a complete physical theory in its own right, but rather a framework for the construction of physical theories." I found this in Michael Nielsen's blog and elsewhere. I am perplexed. In what fundamental way does it differ from Newtonian Mechanics (Theory) in not...

Homework Statement Can anyone please give me hard and interesting problems regarding fluid mechanics problems such as hydrostatic and air prssure bouyance force and Bernoullis equation(Bernoullis equation problems only for liquids)? I tried looking for them but the ones I found were quite...

Homework Statement I'm having some issues understanding a number of concepts in this section here. I attached the corresponding figure at the end of the post for reference. Issue 1) 1st of all, I understand that a Hamiltonian can be written as such $$H = T_2 - T_0 + U$$ whereby ##T_2##...

Homework Statement I have the answer for part a, which is: $$\theta '' + \frac{a}{r} \cos \theta + \frac{g}{r} \sin \theta$$ My issue lies with getting the following equation of motion for part b, $$\theta '' + \frac{g}{r} \cos \alpha \sin \theta = 0$$ Homework EquationsThe Attempt at a...

Homework Statement I am referring to this thread and question: https://www.physicsforums.com/threads/rotation-of-a-spool-about-rough-ground.295666/ Here is the problem, restated: Homework Equations ##\tau_{net} = I\alpha## ##\tau = Frsin(\theta)## ##F_{net} = Ma_{cm}## ##\alpha = a_{cm} /...

Homework Statement Assume that m(fuel, climb) = 1300kg is the mass of fuel required for the climb to the cruising altitude of 10,000m, independently of the take-off weight. Assume that the distance covered during the climb is always 100km. Consider the typical payload-range diagram shown and...

It seems like every argument in favor of the Simulation Hypothesis revolves around the strangeness of Quantum Mechanics. So can the Simulation Interpretation be just as valid of an interpretation as Copenhagen or Many Worlds? If not why not?

Homework Statement In this diagram, I wondered if there is any torque due to the normal force from the hinge, once the support stick is removed. I also want to know what the normal force would be at the hinge. The cup and ball are to be ignored here (essentially massless). Homework Equations...

Homework Statement The skier is skiing without friction down the mountain, being all the time in a specified plane. The skier's altitude y(x) is described as a certain defined function of parameter x, which stands for the horizontal distance of the skier from the initial position. The skier is...

Hello, I am trying to "integrate into my understanding" the difference between Hamiltonian and Lagrangian mechanics. In a nutshell: If Lagrange did all the work and formulated L = T - V, they why is Hamilton's name attached to the minimization principle? YES; I KNOW about Hamilton's Second...