Frame Definition and 1000 Threads

If a solid object rotates at constant angular velocity, is it possible to chose an inertial reference frame in which the object will not rotate?

I am confused about the twin paradox. Let's imagine Mike and Angela are twins. Mike stays on Earth, and Angela rockets off, away from Earth at close to the speed of light, with the intention of making a round trip back to Earth at the end of her voyage. My question is this: why wouldn't...

Homework Statement This isn't a homework problem but rather a problem I need to solve for a personal project of mine. Basically I need to find the moment of inertia of the following: http://img860.imageshack.us/img860/3952/roboframe.jpg Uploaded with ImageShack.us The rotation is with...

From http://en.wikipedia.org/wiki/Frame-dragging" : "Under the Lense–Thirring effect, the frame of reference in which a clock ticks the fastest is one which is rotating around the object as viewed by a distant observer. This also means that light traveling in the direction of rotation of the...

Homework Statement Usually in physics problem on special relativity, the state that this particular spaceship is traveling at, say, 0.6c. Question is, where does this 0.6c come from? If the speedometer in the cockpit reads 0.6c, does it mean that the observer will look and think that it...

I am trying build a frame in mass production with the aluminum profiles but always have the problem at the mating region of the profiles. As you see in the picture, there is always a line at the mating region of the profiles. Is there anyone who can help me about this problem? Do you know...

A moving charge constitutes current, which in turn produce magnetic field around it. So does that mean if the observer is also moving with charge, then it will not experience ne magnetic field? And if the same observer is carrying a permanent magnet, then it will not show ne motion to align...

I have a digital photo frame that's pooped out on me. In attempting to replace it, I am really disappointed with the digital photo frames I've looked at at Best Buy. Half of them did not work and the other half were so unintuitive that I could not figure out how to operate them without the...

The Earth is an approximately inertial reference frame since it's acceleration with respect to the stars is very small. But if a group of stars is accelerating with respect to another group of stars which group is the inertial frame? Or thinking on an even larger scale, if a universe is...

Homework Statement I'm required to assign co-ordinate frames to an RPR robotic structure, using the Denavit-Hartenberg notation. Homework Equations N/A The Attempt at a Solution I've made the following two attempts at the problem, but i aren't sure which, if any, is correct...

So I was pondering long distance space travel. As I understand it, if you can accelerate a vessel, say over the course of a year, to near light speeds, you can cover very very long distances in a very short period of time(as measured on your on space ship) due to the effects of relativity...

Homework Statement Last week I https://www.physicsforums.com/showthread.php?t=483819" which I believe didn't get answered because my description of the problem was a lot messier than it needs to be. Hopefully today, I will not make the same mistake. In physics books, when calculating the...

Homework Statement A 0.150 kg frame, when suspended from a coil spring, stretches the spring 0.050 m. A 0.200 kg lump of putty is dropped from rest onto the frame from a height of 30.0 cm The collision between the two is perfectly inelastic. Find the maximum distance the frame moves downward...

Einstein's theory of relativity is based on the fact that all motion is relative, which precludes the existence of a universally defined state of rest (priviledged reference frame). Einstein also recognises the existence of rest mass. If an object were at its rest mass, wouldn't it be perfectly...

hi, I've been toying with the idea of converting my mini cooper to an electric car, and I'm brainstorming ways to reduce the weight as much as possible. I came up with the idea of a carbon fiber frame to replace the heavy steel one, I found a company that can do it for me, but I was wondering...

Okay, so I know what inertial and non-inertial frames of reference are: 1. Inertial is when Newton's laws of motion hold. 2. Noninertial is when they do not hold (the object is accelerating without a force). And I have a few examples as well, such as when you are is in a car and the car is...

I've been learning about 4-velocity and all the "proper" 4-vectors recently, and if I understand correctly, proper velocity η (the 3-vector) is related to ordinary velocity by the relation \vec\eta = \frac{\vec u}{\sqrt{1-\frac{u^2}{c^2}}}, where u is ordinary velocity of an object within a...

Homework Statement In a certain reference frame, a particle with momentum of 4 MeV/c and a total energy of 5 MeV (a) Determine the mass of the particle. (b) What is the total energy of the particle in a reference frame in which its momentum is 4 MeV/c? (c) What is the relative speed of the two...

Let a clock A be at rest in an inertial frame and let a clock B rotate around it with constant velocity and constant distance from A. Let v be the velocity of B relative to the inertial frame. Both clocks count how long it takes for B to rotate once. According to clock A, the time it takes is...

Does light beam create linear frame fragging around it? If answer is positive, can light become 'tired' going thru the universe and exchanging the momentum with the environment via frame dragging?

1.0 Introduction As the thread title suggests, this is indeed referring to a lab experiment. I am not posting here to gain easy solutions to the lab manual questions, rather I'm posting here to gain knowledge on a subject I know very little about. Let me explain the lab experiment in detail so...

Homework Statement A man of weight W is in an elevator. The elevator accelerates vertically up at a rate a and at a certain instant has a speed V. The man then climbs a vertical ladder within the elevator at a speed v relative to the elevator. What is the man's rate of expenditure of energy...

I have been doing some study on the theory of relativity and it has got me thinking. We say that the Earth revolves around the Sun but from what reference frame? From the reference frame of Earch, we are stationery and the Sun simply spins. Why is any reference frame more accurate than another...

The wikipedia article on connection forms refers to a local frame. What is the relationship between local frames and coordinate bases? Are they the same thing? Is one a subset of the other? The connection form article uses general notation e_\alpha for the basis elements instead of the...

I've read that in relativity the concept of the rest frame of a photon doesn't make sense. Why is that? A rest frame of some object is a reference frame in which the object's velocity is zero. One of the key axioms of special relativity is that light moves at c in all reference frames. The rest...

My thinking has been that a photon, in its own F of R, in a vacuum, travels through space, but not through time. This seems to have been "confirmed" in various things I have read. However, I recently came across the assertion that "...in physics, there is no theory that defines the frame...

If the equivalence principle is true then it means that the Earth's gravity field is a constantly accelerating frame of reference. In any accelerating frame of reference the direction of acceleration is always opposite to the direction of attraction. That means that for all observers on the...

Homework Statement The Attempt at a Solution I'm going to post all that I figured out or tried. Most of it is really just pieces of information that I don't know how to put together. The frame is accelerating, so I have to apply a pseudo-force of \frac{3mg}{2} on B and C in the...

Homework Statement An isolated, thin, rigid, spherical shell has mass M and radius R. If the shell is set slowly spinning with angular momentum J, show that inertial frames within the shell rotate at angular velocity w with respect to an observer at rest at infinity, where: w=2GJ/(c^2*R^3)...

Hi. I'm a sophomore level undergrad trying to understand General Relativity (and all of physics for that matter) with the currently insufficient tools I possess. I was reading Einstein's book, "Relativity", and when I came to the section that describes gravity as the apparent force that arises...

Homework Statement To rods, each with mass 0.3 kg and length 0.2 m, are welded together at one of their ends, so they form an L-shaped frame. A ball with mass 0.3 kg and with speed 5 m/s hits one of the rods at its end at an angle of 0 degrees (so ball speed vector is perpendicular to one...

A 3 pin frame ABCDE is supported at A and E. it supports vertical loads of 60 kN at B 80 kN at c and 100 kN at D as well as a horizontal UDL of 50kNm along DE. Calculate the reaction forces. I have REV = 124 kN and RAV = 116 kN. REH = 115.3kN and RAH = 215.3 kN. Are these correct Next...

***not homework for any class*** Title: "Preserving Magnetic Polarity in a Revolving Reference Frame" Problem: How can a revolving reference frame (assuming an uncharged observer with negligible mass) observe the same polarity for a magnet in the case where the rotational speed is great enough...

Hello, apologies if this has been asked before but I couldn't find it upon searching... My block to understanding general relativity has always been how the idea of gravity being the same as an accelerating frame leads to a a curved space-time? What about the fact of not knowing whether...

Hi i have a problem with some work. a muon type neutrino interacts with a stationary electron, producing a muon and electron type neutrino. I have calculated the CM energy but now need to calculate gamma, the lorentz boost. γ=(Eν/2me)^1/2 How do i show this? the info i have is that...

So I was studying some physics, and I keep encountering how many things depend on the frame of reference. For example, kinetic energy and momentum. My question is if there is an absolute frame of reference? Can we define one? I remember reading somewhere that the absolute reference...

Hi, I have a simple question in my mind, I could not find the answer anywhere so I came here. Here is my question, Assume a source of light and observer are five light seconds apart, and are travling parllel to each other at a constant speed of say 200 meters per second. Now if the source of...

Please teach me about this: Are there any change in energy and momentum of photon in different frame?Are there any analogies with Doppler effect? Thank you very much in advance.

Hi all, Trying to design a simple gate for the side of our house and in order to select the size of the square tube for the frame, I need to calculate the forces in the members of the frame. I have tried the method of sections and joints, however both do not seem to work. My next...

Hello :) An object is placed far away from all the bodies that can exert force on it. A frame of reference is constructed by taking the origin and axes fixed in this object. Will the frame be necessarily inertial? Hmm According to me, it should be an Inertial frame as No force acting on it...

Objects smaller than black holes, by mass can still drag space along with their rotation. I picture this like a plate of Spaghetti there the pasta is radiating out from the center of the plate. But let's say its rubbery spaghetti and can stratch. And its attached at one end to the outer egde of...

Hi there, I've got an assignment due today and as usual have left finishing it off until the last minute. I've completed most of it but I thought I'd try and get an opinion on something. Homework Statement Basically our teacher has asked us for a very simple steel frame (beam, column...

me and my friend were arguing (like always) about inertial frame ? to sum up i m just asking a straightforward question ? let say (for simplicity) there is just Earth and an other object in whole universe. a point whose distance from Earth is x. and dx/dt = 0. now is that point (which...

Hi: I’m a new member to this forum. I’m looking at the behavior of frame dragging around a rotating black hole. It seems to me that frame dragging should be zero about a rotating black hole’s axis of rotation, but should be at a maximum at the equator (i.e. 90 degrees from its axis of...

Homework Statement Located here:http://imgur.com/qP9fd.png" The Attempt at a Solution I don't know how to do this problem. First of all how do I approach it? Should I do a free-body diagram? Should it be done at position 1? How do I account for the different frame of reference...

Homework Statement A student is in a rotating chair with a pendulum hanging down in the middle of the rotation. . I need to calculate the difference in tension when the bob is hanging vertically and when the chair is rotating. The length of the bob and string is 65.3 cm. The radius of the...

Hi, I'm stuck with a question concerning electric fields : Can an electrostatic potential drop exist in (what I would call) a 0 dimensional system ? Let's imagine we are in a region of space where there is nothing but a uniform magnetic field. So the problem is anisotropic but does not...

Major difference of Inertial and non-inertial frame of reference ?? What is the major difference or differences of Inertial and non-Inertial frame of reference?? Is it only: Inertial - Constant velocity, obeys the law of inertia Non-inertial - Acceleration, disobeys the law of inertia

Hi all, I massively appreciate any help in advance. I have an exam coming up and am completely stumped on a question regarding reinforced concrete design. The teacher has told us the question is going to be similar to the example he has given us but hasn't gone through it with us. It is a...

Earth is clearly not an inertial frame, its in orbit and not following a single direction of movement. Why then do we treat it as one? Are there any slight differences in the laws of motion in a true inertial frame in contrast with those on earth?