Frame Definition and 1000 Threads

For some reason I've thought about the following case : A uniformly non conductor charged disk is rotating with an angular velocity \vec \omega. If I see it in front of me I'd observe a magnetic field since moving charges produce a current which produce a magnetic field according to Ampere's...

Homework Statement Calculate, to first-order in beta, the way the coordinates transform when velocity is a function of time. Homework Equations Poisson-bracket relations for Poincare group? Also: expression of any dynamical variable as an n-applied Poisson-bracket in a Taylor-series...

Is it safe to say that any object in an inertial reference frame is at a state of equilibrium? If so.. is it safe to say the opposite: that any object in a state of equilibrium is in an inertial reference frame?

OK, here is an interesting assertion I haven't seen before. Thought I would see what some of the folks here think. The paper is: Quantum Preferred Frame: Does It Really Exist? by J. Rembielinski, K. A. Smolinski (2009) Abstract: "The idea of the preferred frame as a remedy for...

Homework Statement A rocket travels in a straight line with speed 0.6c, where c is the speed of light in a vacuum. A wrist-watch is on board the rocket. The rocket moves past a clock tower on the earth. a. In the inertial frame where the tower is at rest, how long does it take the watch (on...

Hi I'm trying to define a Newtonian lagrangian in an rotating reference frame (with no potential) Something to note is that the time derivative of in a rotating reference frame must be corrected for by: \frac{d {\bf B}}{dt} \rightarrow \frac{d {\bf B}}{dt} + {\bf \omega} \times {\bf...

Is the Change in Rotational Kinetic Energy Frame Invariant? -------------------------------------------------------------------------------- I know the translational kinetic energy of an object is frame dependent. That is, in the center of mass frame of the object, the kinetic energy is...

When talking about the translational velocity of a rigid body in physics, the velocity is always frame dependent, and therefore, the translational kinetic energy is frame dependent. But does this apply to angular rotation phenomenon? If in one frame, the angular velocity of a rigid body is 10...

Sorry if this has been asked, but I did a search and didn't find a relating topic. This thought came to me a few days ago when a friend asked me about time dilation. Time beats slower and distance is shorter for a moving reference frame with respect to a non-moving reference frame, and the...

Homework Statement A picture frame hung against a wall is suspended by two wires attached to its upper corners. If the two wires make the same angle with the vertical, what must this angle be if the tension in each wire is equal to 0.75 of the weight of the frame? (Neglect any friction...

I am confuse of what is inertial frame of reference. Can someone explain that to me? I need a clear explanation starting from the beginning to the end, and if possible, give me some set of example.

What does Special Relativity imply about past, present, and future time? So, here on earth, what can be said about our understanding of past, present, and future actions? Within the same reference frame, is time static? Is it ordered?

Hi guys, I was reading the derivation of ficticious force due to moving frame of reference however i don't understand how they did it.There wasn't detail explanation for slow learners like me so i was wondering does anyone know where i can read up on this or give me some clue where i can start...

Hello Forum, Using a fixed, Cartesian reference frame (i.e., we, observers, are stationary and located at the origin of the system), the trajectory of a particle would be easily described by the parametric (parameter time or arch length) equations [x(t), y(t), z(t)] or [x(s),y(s),z(s)]...

Homework Statement blah blah blah Homework Equations momentum = momentum' mv + mv = (m1+m2)v (Uk)N = friction force The Attempt at a Solution It's hard to find how to start with randomly given values. Thank you so much for your help! :D

Homework Statement At apparent latitude 45◦N a shell is fired due North at an inclination of 45◦ to the horizontal with initial speed V . Show that, neglecting the curvature of the Earth, the shell will hit the ground at a point a distance \frac{2 \omega V^3}{3g' ^2} East of the line of...

Homework Statement http://img198.imageshack.us/img198/3834/relativeboatvelocity.jpg The note says "( Wind relative to boat is irrelevant! )" Why is it irrelevant?

Frame Analysis Using Method of Members. Determine the force in bar BE. 2. Well, I don't know where to start. I know there are three equations EFy=0, EFx=0, EMc=0 but I don't know what the first member to consider and how to solve this type of problem. There is a final answer given, BE =...

1. Determine the type and magnitude of force in bars BD and BE using method of members. 2. Well, I don't know where to start. I know there are three equations EFy=0, EFx=0, EMc=0 but I don't know what the first member to consider and how to solve this type of problem. 3. There is a hint that...

Could anyone help me on this question: Suppose ${e_i}$ is an orthonormal frame, is $\nabla_{e_1}e_j$ is 0 if i is not equal to j? Any answers or suggestion will be highly appreciated.

If we can shoot a photon outward, at velocity c, why is it that the body that shot it outward is not traveling away from the photon with velocity c?

Is a falling elevator a valid inertial frame? The title about says it. Is a body, (frame) free falling in a gravitational field a valid inertial frame as defined by SR? Thanks

Hi, I was wondering: I'm sitting at my desk and on my desk lies a pen. Does the pen describe a geodesic? And is the room I'm sitting in an inertial frame? I think the pen doesn't describe a geodesic because it's not in free fall and i think my room is a good approximation of an inertial...

Briefly describe a sidereal frame of reference, and then state Newton's laws of motion I can't find sidereal in the index of my textbook, but my googling leads me to conclude that it's something to do with fixed stars. I'm not sure if a sidereal frame is also an inertial frame. Newtons laws...

Hi every one. As Steel Frame Manuel mostly discribe the force analysis in vertical loading, I wonder how can i solve the following case, a member that suffer torison. Is there any reference book you might suggest me to read ,too? Thanks for your kind help. The attached are the cases...

Hi. Say a particle is moving around in uniform circular motion. The way my book attacks this problem is by placing the coordinate system such that one axis is in the radial direction and the other axis is in the tangential direction. Then we have the following for the radial acceleration...

Hi, Myself and my friends fabricated an equipment for electrospinning- a process used used to produce nano fibers. The objective of the work is to get ordered arrangement of nanofibers(we referred a journal). But when it was put to test, it didnt work as expected:-( Please check out the...

Dear PF could you advise me Whether I understand properly or not: In an arbitrary space-time (with an arbitrary curvature) in any sufficiently little region we can go to Local Inertial Frame of Reference - sit into the free falling lift. Being there our experiments are the same as we have...

Hi How do you calculate the natural frequency and vibrational response of a space frame and what is its damping characteristic? What are all the aspects to take into considerations and how do you analyse failure due to vibration? Thanx

Hi all Why do we actually say that Newton's laws do not hold for non inertial frames. can you folks give me an example of how Newton's laws collapse in an non inertial frame(if they do at all)

Homework Statement Hi, I am working on a camera system in flash, and am trying to implement an ease in/out effect where the camera moves between two points, with positive acceleration up to the midpoint, and then negative accelaration up to the end point. I've had a look through the equations...

Hello I'm a visual artist and I'm trying to make a project were I need to add a sound to a photograph hang to a wall in a picture frame.The source of the sound it will be a ipod (unless someone has a better idea)I need to build a device to make the music from the ipod place in the narrow place...

Homework Statement I need to verify a couple of unknown forces in a truss, attached image (all individual trusses are 300mm in length) Homework Equations Determine the forces in trusses shown. The Attempt at a Solution This is a lab and I've used a telescopic gauge with a...

Hi I need help for this structure. It is loaded as shown - point E and G is wheels added as free bearings. I need to know the bending in Beam AD and also EF. I tried isolating beam AD and see it as an statically inderteminant beam to the second degree - but i am not sure this is the right...

Is temperature frame dependent? The temperature of the system is due to the translational,rotational and vibrational movements of the particles of the system Now if a box containing gases at a certain temperature is accelerated the molecules in the direction of motion of the gases get more...

I was thinking about something earlier today. One of Einstein's famous phrases is "I can not believe God plays dice with the Universe." After pondering on this for a while, something confused me. Say for example we have a group of observers who all observed the Simultaniety of an event...

Hey i would really appreciate it if someone could help me with the load calculations in a chassis. The frame is basically a ladder frame, 2 C section side rails and cross members. Would like to know how the weight of the vehicle acting at the Cg gets distributed along the frame. And how does...

Homework Statement I need to find the Exact Solution for this problem(Displacements) I already did it using MATLAB but I need to compare it to the exact solution I am not sure what equations to use for this problem and where to start? Homework Equations -Plane strain -E and v are...

Homework Statement Basically, I am looking to find the reaction forces at the pin joint on the right side of the structure. I just realized it is not labeled on my diagram, but it is the pin on the link opposite of E. Where the 13 degree angle is measured from. Homework Equations I have...

hey guys, this may sound dumb, but if it takes an observer to collapse a wave form and create reality, and if the human eye works at about 25 frames per second, does that mean that we only create everything around us every 0.04 seconds? thanks.

Homework Statement Show that as calculated in the rest frame comoving with the twin on the outgoing trip, the ratio of the two ages of the twins is the same: i.e. the twin on Earth has age gamme times the other twin Homework Equations Lorentz Transforms The Attempt at a Solution We...

collisions and "changing frame of reference?" Homework Statement A 6.0Kg trolley moving at 6.0 m/s right overtakes and collies with a 2kg trolley moving 2m/s right in the same direction on the same track. The collision is cushioned by a perfectly elastic bumper attached to one of the trolleys...

While explaining about inertial and non-inertial frame of reference, people give this example-- http://www.phys.unsw.edu.au/einsteinlight/jw/module1_Inertial.htm if you don't wish to follow the link, here is a simple explanation---> there are two person and a rotating disk. Person A is in...

In this problem we will examine the collision between a baseball (the cowhide) and a bat (the ash). We assume a one-dimensional problem. That is, the bat hits the ball squarely, so that the ball reverses its direction after the collision. We also assume that the ball hits the bat at the center...

Homework Statement A particle of mass M is hanging from one end of a massless spring, while the other is attached to the ceiling of an elevator. The elevator then starts to move upwards at an acceleration equal to g/5. Which way does the equilibrium shift, and what is the magnitude of...

I'm new to the study of SR and GR. I have a question that I have not been able to find any discussion about. In the case of two frames of reference where we are comparing events from the point of view between a 'stationary frame' (inertial) to an excelerating frame like the twin paradox is...

Hi guys, I want to check that I am going about this problem in the right way: The attached image shows a parallelogram type frame with a hydraulic ram located from corner to corner as shown (E to C). There is a load applied to a platform in the far bottom right hand side of the drawing...

Hi guys, I want to check that I am going about this problem in the right way: The attached image shows a parallelogram type frame with a hydraulic ram located from corner to corner as shown (E to C). There is a load applied to a platform in the far bottom right hand side of the drawing...

Dear Friends A fleet of spaceships is given, each equipped with a differential microwave radiometer, just like COBE was, whose detectors are antipodeanly pointing (this way one should catch blue shifted radiation and the other one red shifted). Could their acquisitions be used to...

F= q(v x B) B= v x q*k*d/r^2 It is a basic physics knowledge magnetic field forms around moving charge, it tell us magnetic field is zero when charge is not moving and strength of magnetic field increases as velocity increases, right? Magnetic potential vector field increases with "absolute...