Newtonian Definition and 327 Threads

From what I have learned so far, it appears that a light emission orthogonal to motion acts exactly like a Newtonian massive particle with conserved longitudinal momentum. Is this correct? If so it would seem to be a cosmic coincidence of monumental proportions. Having given it some...

Hello. I've recently been working on the mathematics of atmospheric/stellar density, but I've run into an apparent paradox with the assumptions I have been using. I hope this is the right forum for this question. At the moment, I'm working on the equations for the atmospheric pressure/density...

A very simple way to explain the observable universe expanding: Perhaps there is just a bunch of matter surrounding the observable universe and all the observable stars/galaxies are moving per the gravitational field created by matter outside that we have not yet seen. Thoughts?

This paper, written by a University of Pittsburgh professor, John Norton, describes a simple situation in which Newtonian mechanics allows for purportedly non-deterministic equations of motion: http://www.pitt.edu/~jdnorton/papers/DomePSA2006.pdf In the first part of the paper, he describes the...

Last week there was a documentary program on Nat Geo I believe having to do with the composition and origins of comets. The narrative seemed to imply that comets originate within & are rather randomly dislodged from a spherical shell around the Solar System called the Oort cloud. This...

Actually i never got this concept clearly in my mind. What is the meaning whern we say that the energy of a body is negative? For example in Bhor's atomic model we have calulated the total energy of an electron to be negative. Please explain me by using Newtonian Mechaincs as i am the...

I don't have the books in front of me so I only use my memory. According to my professor and if I remember well, Landau and Lifgarbagez, the Lagrangian of an isolated particle can in principle depend on \vec q, \vec \dot q and t. Therefore one can write L(\vec q, \vec \dot q , t). With some...

Hey guys, Was wondering if anyone has seen this done? Essentially I've tried plugging in the Schwarzschild exterior metric and getting a radial wave equation then taking a series expansion for small M (gravitating mass) and comparing that to the KG radial wave equation in a radial potential...

I'm still on special relativity, and haven't yet reached general relativity, but had a question in mind... does the Newtonian description of Gravitational Potential Energy U= -G \frac{M m}{R} fail for very strong gravitational fields? or it only fails where curvature of space becomes...

I've been told for many years now that the speed of Newtonian gravity is infinite. However, I've never received an explanation (or derivation) as to why this is that completely satisfies me. Even the explanations in textbooks (e.g Hartle) seem lackluster to me. So let's see... The field...

Homework Statement a man with mass m=66kg is standing on top of a platform with mass M=120kg. The man is pulling himself up using a pair of ropes suspended over massless pulleys. he pulls each rope with force of F=600N and is accelerating towards the ceiling at acceleration a. g=9.8 m/sec^2...

Homework Statement A 2.0 kg block rest on a 4.0kg block that is on a frictionless horizontal table. The coefficients of friction are u_s = 0.3 and u_k = 0.2. What is the maximum force F that can be applied to the 4.0 kg block if the 2.0 kg block is not to slip? If F has half this value, find...

Homework Statement 1.The work required to lift a mass one meter depends on the speed at which it is raised.. 2.The acceleration of an object is same in all inertial reference frames. 3.A particle's kinetic energy can change without having any net work done it. 4.The work done by...

([SIZE="2"]Moderator's note: thread moved from "Differential Equations") A parachutist whose weight is 75 kg drops from a helicopter hovering 2000 m above the ground and falls towards the ground under the influence of gravity. Assume that the force due to the air resistance is proportional to...

([SIZE="2"]Moderator's note: thread moved from "Differential Equations") A particle of mass m which moves along a horizontal straight line with a velocity of v encounters a resistance of av + b(v^3), where a and b are constants. If there is no other force beside the resistance acting on the...

Understanding the short-distance behaviour of gravity is crucial for constructing a quantum theory of gravity. The Newtonian inverse square law approximation has been tested in laboratory down to millimeter scales, but I'm not aware of any laboratory scale experiments testing general...

hey everyone I'm in year 12 physics, and we have a project revolving around the physics of sport i selected golfing, and my initial aim is to investigate the inaccuracy associated with predicting the aerodynamic motion of a golf ball (max height, max distance). i selected this mainly...

Hey guys, Im trying to derive the following equation (mc^2) [(1/E2)-(1/E1)]+cos(theta)-[((E1-E2)^2)/(2E1E2)]=1 E1 = Incident Photon's energy E2 = Scattered Photon's energy theta= scattering angle m = mass of electron c = s Using conservation of energy,conservation of mass, and...

Homework Statement Derive the equation non-relativistic equation for Compton scattering (mc^2) [(1/E2)-(1/E1)]+cos(theta)-[((E1-E2)^2)/(2E1E2)]=1 E1 = Incident Photon's energy E2 = Scattered Photon's energy theta= scattering angle m = mass of electron c = s Here is the lab In...

Hello all, First and foremost, I want to apologize if I am posting in the wrong area. Please inform me if so. I am new to the forums (hence my first post), and will be doing my first Physics course this winter (starts after New Years) since 2002. I really need to do well, and I have the...

I thought of this problem recently and I was amazed at how difficult it was to solve, given the simplicity of the statement of the problem. I still have no idea how to solve it. The problem is thus: two point masses of 1 kg each are spaced 1 meter apart in a vacuum in space, with no other forces...

In what situations do Newton's law of universal gravity fail to predict correctly how matter moves? The examples I know of are frame dragging (around rotating BH), shifting of light paths, shifting orbits of planets. But does Newton's law really predict the magnitude of gravity accuratly? How...

How to calculate the shear rate for the flow of a shear thinning liquid in a non circular duct

Homework Statement Two forces act on an object of mass 2.5kg; force F1 that is directed alont the +x-direction and has magnitude of .50N and force F2 that points at a 45 degree angle in the +y and -x quadrant and has magnitude 2.0N. Find the additional force, if any such that the object will...

Homework Statement A person weighing 55kg jumps off of a bridge with a bungee cord attached. The problem seeks to find the bungee cords Force vector when the acceleration is 7.8m/s2 in the downward direction. m = 55kg a1 = g = 9.8m/s2 To find: F1 when a2 = 7.8m/s2 downward. I've...

Homework Statement These are all true/false questions. 1. The acceleration of an object is same in all inertial reference frames. 2. The work required to lift a mass one meter depends on the speed at which it is raised.. 3. The work done by a constant force acting on an object is...

Homework Statement Consider a particle of mass m whose motion starts from rest in a constant gravitational field. If a resisting force proportion to the square of the velocity (i.e. kmv^2) is encounterd, show that the distance s the particle falls in accelerating from v0 to v1 is given by...

In another thread a discussion arose about the interpretation of derivatives. For example acceleration is the time derivative of velocity. Obviously, in the strictly mathematical sense: in relativistic physics and classical physics alike acceleration is the time derivative of velocity...

Homework Statement Question 1: Is Ohm's Law (V = IR) invariant under Galilean transformations? Question 2: Model the Earth as an ellipsoid or a spheroid, and find the lowest order correction to the inverse square law at points inside and outside the Earth's surface. Homework Equations --...

I'm reading A Brief History of Time by Stephen Hawking and he says that "gravitational effects should travel with infinite velocity" if an object is moved and therefore the gravitational force between them is instantly changed. this gravitational force then moves faster than the speed of light...

I am trying to simulate a square object affected by a force in two dimensions. I can break up the force vector into a vector whose extension intersects the center of gravity for translation and a vector perpendicular to that for rotation. My question is: how does this rotational vector relate...

I'm trying to find a divergenceless vector field based on its curl, and discovered that I could use a http://en.wikipedia.org/wiki/Helmholtz_decomposition" , and the article I found on this didn't make much sense to me. First, can someone confirm that the dimension referred to in the...

I'm trying to find a divergenceless vector field based on its curl, and discovered that I could use a http://en.wikipedia.org/wiki/Helmholtz_decomposition" , and the article I found on this didn't make much sense to me. First, can someone confirm that the dimension referred to in the...

What exactly was wrong with Newtons gravity. I understan that GR says that gravity is the curveture of space and time. However if Newton was wrong wouldn't that mean that F= GMm/d^2 is actualy wrong?

Homework Statement For a perfect fluid verify that the spatial components of T^{\mu \nu};_{\nu} = 0 in the Newtonian limit reduce to (\rho v^{i}),_{t} + (\rho v^{i} v^{j}),_{j} + P,_{i} + \rho \phi ,_{i} Homework Equations Metric ds^{2} = -(1+2 \phi )dt^{2} + (1-2 \phi) (dx^{2} +...

Would someone please help me in thinking the following out: I was taught that the Newtonian gravitational potential was given as -Gm/r; and when examining a sphere of uniform density ρ and radius r, then at any point x ≤ r (within the sphere), m would refer to the effective mass of an...

I'd appreciate any explanations and maybe an available source that discusses how and why time is relatively more curved than space. Is there is particular source for time curvature in the stress/energy/momentum tensor?? Thank you.

Homework Statement Given if: (1) Fsm + Fem = Mm x Ams (2) Ams = Ame + Aes (3) Res ~= Rms Show that (4) Fem ~= Mm x Ame Where: 'Fsm' is the force between the sun and moon, 'Fem' the force between Earth and moon, etc. 'Mm' is the mass of the moon, 'Ams' the accelleration of the...

What are the factors that affect viscosity of incompressible Newtonian fluid? Here is what I think: Temperature: When we increase the temperature of a fluid (controlled volume) the frequency ofintermoleculer collisions increases. Does this mean viscosity decreases? And if so, does...

I seem to recall reading a post a long time ago (that I cannot find) that gravity in the Newtonian limit (eg the Solar system) can be completely explained in terms of gravitational time dilation alone. In his book, Gravity from the Ground up, Schutz argue that All of Newtonian gravitation is...

I've recently been looking at the way in which pressure terms contribute to the Komar expression for the total energy in GR and I've been trying to understand the Newtonian equivalent. I found something which surprised me, and I'm wondering if it's well-known: If you take a couple of masses...

Homework Statement Ugh, rusty on my Newtonian Mechanics and need to refresh. I picked out this problem in my book: Two boxes are on a 30 60 90 triangle. Box 1 is on the 60degree side and Box 2 on the 30degree side. The ramp has two different coefficient of static friction: u1 (for box 1)...

Before I begin, let me say this is my first time on this forum, and am terribly sorry if I screw something up here. Let me also say that my physics lab is ahead of my physics class, so my knowledge on angular momentum is lacking. Also, this lab is due tomorrow. I know it's short notice, but I...

Homework Statement http://img399.imageshack.us/img399/4277/cartyf8.jpg http://g.imageshack.us/img399/cartyf8.jpg/1/ Homework Equations Euler's Method, Runge Kutta 4th Order Method The Attempt at a Solution I have solved the motion equation for the above question using Euler's Method and...

Homework Statement Im doing a philosophy, history and politics of science subject and the question is whether gravity was waiting to be discovered or was it an intellectual construct particular to the 17th century and Newton. Homework Equations The Attempt at a Solution I'm...

The Newtonian limit for general relativity exists only for the asymptotically flat spacetimes. FRW case definitely not asymptotically flat. SO the Newtonian limit should not exist for it. However we have Newtonian theory of cosmology in homogeneous and isotropic universe. So my question is...

This Brownstein/Moffat paper (arXiv:astro-ph/0702146v3, 13 Sep 2007)) looks interesting to me but it's too deep for me to really understand. The gist of it seems to be: ===quote=== The alternative to the dark matter paradigm is to modify the Newtonian 1/r2 gravitational force law so that the...

Homework Statement In a lab frame of reference, an observer finds Newtons second law is valid in the form of Fnet=ma. Show that Newtons second law is not valid in a reference frame moving past the laboratory frame of problem 1 with a constant acceleration a1. assume that mass is an invariant...

Hello, this question is about lift in fixed wing flight (airplanes). Is it possible to calculate separately the lift generated by: - Newton's laws (wings deflecting air particles) - Bernoulli effect (difference in air pressure above and below the wings caused by the shape of the...

Consider two point mass particles m1 m2 (with m1 different from m2) initially stationary relative to each other a distance x apart . The only force acting on them is attractive Newtonian gravity, i.e. Gm1m2/x^2 acting equally in opposite directions along the line of separation between the...