Frame Definition and 1000 Threads

A vehicle frame, also historically known as its chassis, is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism.
Until the 1930s, virtually every car had a structural frame separate from its body. This construction design is known as body-on-frame. By the 1960s, unibody construction in passenger cars had become common, and the trend to unibody for passenger cars continued over the ensuing decades.Nearly all trucks, buses, and most pickups continue to use a separate frame as their chassis.

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  1. M

    Bead on loop of wire in rotating frame

    Homework Statement Consider a bead sliding without friction on a circular hoop of wire rotating at constant \Omega, where \phi is the angle between the bottom of the hoop and the bead. Find the equation of motion of the bead. \hat{\Omega}=\hat{z} Homework Equations...
  2. P

    Is Radiation a Frame-Variant Process?

    Hi, Is radiation a frame variant process, which means for example, if someone is co-accelerating with an accelerating charge(such that no relative motion) then he will not witness radiation since to him, since the charge is stationary. However, to an inertial observer outside, he will...
  3. H

    Time Dilation: What's the Rest Frame?

    I really don't quite understand the result of time dilation. Let's say that we have two identical twins A and B. Twin A is at rest and twin B is on a high speed rocket ship. Let's say that 10 years has passed in frame A. According to relativity, the twin in frame B is supposed to measure less...
  4. B

    Problem in inertial reference frame

    Well, in principle, this problem seems very easy but I don't know the exact explanation.Here we go. We have a truck and a pack in its back.The bed of the truck is frictionless and the pack is stopped by a small piece of wood of something like that. The size of the pack is whatever(for...
  5. A

    Solving Rotating Frame Problem: Need Help!

    i am facing problem in attempting the peoblem attached below if i work in the non inertial frame (the rotating) shouldn't the acceleration of m_a after the catch is removed be simply =\omega2ra thanks in advance
  6. T

    What Defines the Total Momentum in the Center of Mass Frame?

    Homework Statement A key concept about the center-of-mass frame is that A. the total momentum in the center of mass frame is always zero. B. both the initial and final momentum vectors form pairs of equal magnitude and opposite direction C. this frame always moves at the same velocity...
  7. B

    How to show time ordering is frame independent

    Hello, everyone I am studying Srednicki's "Quantum Field Theory", section 4 "The spin-statistics Theorem". Does anyone know how to show that "The time ordering of two spacetime points x and x' is frame independent if their separation is timelike."(P32), explicitly? And "Two spacetime points...
  8. P

    Block sliding down accelerated inclined (need inertial frame approach)

    Homework Statement A block of mass "m" is placed on an incline of angle \theta and mass "M", which is placed on a horizontal surface (the ground) and release from rest. Both the block and incline start accelerate. All surfaces are frictionless. Find the acceleration of the block with respect...
  9. F

    Exploring the Frenet Frame Equations for Curves in R_3

    I'm trying to show that the Frenet frame structural equation for a curve in R_3 can be written in the following form for a vector W(s): T'(s) = W(s) x T(s) N'(s) = W(s) x N(s) B'(s) = W(s) x B(s) The problem I'm having here is that I define first that T(s) should be the unit tangent at...
  10. D

    Lead screw and frame calculations

    Hi I am new to the design game as it where and I have scoured books and the internet looking for calcs, examples, help with a design I am putting together which involves raising and lowering a heavy object using a lead screw. I know its not strictly CNC stuff but I believe someone may be able...
  11. Rasalhague

    Local Lorentz Frame: Blandford & Thorne's Applications of Classical Physics

    Blandford & Thorne, Applications of Classical Physics: Taylor & Wheeler, Spacetime Physics: These definitions seem to be based on the notion of a "physical" or "practical" infinitesimal: a quantity too small to be detected. But how can we measure the accuracy of an imaginary detector...
  12. S

    Frame of Reference: Does Stuff in the Frame Matter?

    Okay, weird question. Sorry if this is really stupid but it's been bugging at me for days now. First, let me lay out my current assumptions/understanding of what's going on. The current theory seems to be (to an amateur like myself) that there is no fixed space-time. That to talk about...
  13. M

    How to determine nature of frame (inertial/non inertial)?

    what is inertial frame of reference. lets say motion is in 2d universe (x,t) consider three points f,a and b the distance of a and from f be x and y respectively. for what equation (s) of motion f would be inertial frame of reference for a ? what does it mean that Newton's law hold...
  14. Jonnyb42

    Speed of light in Non-Inertial reference frame?

    I see a lot of places, "The speed of light is the same in all inertial reference frames." But is it the same in non-inertial reference frames too? For example, your reference frame/observer is accelerating according to someone else holding a flash light, at the moment they meet, the other...
  15. R

    Help Analyzing Frame Homework: Find Forces & Best Angle

    Homework Statement http://img571.imageshack.us/img571/2026/framekq.jpg I need some help with finding the forces associated with this structure. I drew it badly from how a friend described it. A point load would be placed on it so, a weight W would be at the centre + the weight of the...
  16. J

    Resolve to the Twins Paradox – Frame of Origin

    I have read many arguments concerning the issue of the famed “Twin Clock Paradox”. Very many arguments go through considerably complex explanations so as to defend Special Relativity or dispute it. But the explanation is actually much simpler. In every proposed twins paradox, there is a Frame...
  17. A

    Why does Newtonian mechanics include relative motion between inertial frames?

    I know that in Newtonian mechanics an inertial frame of reference moves relative to absolute space. But why does Newtonian mechanics include the contention that two inertial reference frames move relative to each other? It seems that if you have an absolute reference frame then there is no...
  18. M

    Help with frame and reference problem

    You are on an airplane traveling due east at 100 m/s with respect to the air. The air is moving with a speed 35 m/s with respect to the ground at an angle of 30° west of due north. What is the speed of the plane with respect to the ground? __________ So here's what I am doing: Drew the...
  19. R

    Coriolis Acceleration and Inertial Frame

    Hi In my textbook they were doing a derivation of the acceleration of a projectile flying on Earth. Although they used the center of the Earth as the frame of reference, they ended up with the linear combination of 3 quantities for the acceleration of the projectile, one of which they said...
  20. A

    What are Some Resources for Designing a Moon Buggy Frame?

    Hi everyone... i have to design the frame of a moon buggy, which is a manually powered vehichle for 2... it is somewhat similar to the frame of FSAE cars... but the problem is... i don't know from where to start... i have ideas... but to design a proper frame... i need some study material...
  21. C

    Potential energy in center of mass frame.

    Homework Statement I am trying to find the total energy of a twobody system (two planets orbiting each other) in the center of mass frame. And I was so wondering how to think about this problem.. I know that the kinetic energy in the center of mass is just the sum of the kinetic energies...
  22. Philosophaie

    Time Frame of Sun on Ecliptic Plane vs Equitorial

    The Earth rotating on its equitorial axis spinning on its poles. The Sun has its orbit on the ecliptic 23 degrees away from the spin if the Earth. Is the time frame different at the Earth on the Ecliptic plane rather than the Equitorial?
  23. S

    Is there preferred reference frame for motion in the universe.

    For a long time, I have wondered if space has a preferred reference frame. As one looks at the cosmic microwave background radiation, ask your self what would it look like if I accelerated myself in one direction. You would expect a bluer shift in one direction and redder shift in the other...
  24. D

    Understanding the Body Frame of a Spinning Symmetric Top

    Hello, I have a question about a spinning symmetric top: When the equations of motion are solved, they are solved in two frames--the space frame and the body frame. I understand the space frame, but in the body frame you are looking at the top from a frame that is rotating with it, right? So...
  25. DaTario

    Experimentally probing the photon's reference frame

    Hi All, Suppose a photon is approaching the origin of set of three cartesian axes, along the negative part of the z axis. If we put a slit, geometrically defined as: 1a) half plane z = 0 and x >= epsilon 2a) half plane z = 0 and x <= -1 * epsilon Note that the slit width is 2 *...
  26. P

    What is the total energy of a simple pendulum in an accelerating frame?

    Homework Statement A simple pendulum that consists of a mass m and a massless cord of length L is hanged on the ceiling of an elevator, which is intially at rest. The pendulum is performing a simple harmonic motion. The energy of the mass (Kinetic energy + potential energy with respect to...
  27. P

    How Does Rotating Frame Affect Friction and Heat Generation?

    http://img14.imageshack.us/img14/1399/blahblahr.jpg Uploaded with ImageShack.us Homework Statement These stairs are rotating as a whole while a dog is climbing on them with a velocity v relative to them, as shown. The angle that these stairs make is 60 degrees, and the radius is R. 1...
  28. D

    De Broglie wavelength and it's dependence of the frame of reference

    Hello, I've always wondered about the "relativity" of the De Broglie wavelength. The wavelength depends on the momentum of the specific thing we are observing, thus on different frames of reference(F.O.R from now on :P) we might get different answers. I have been looking through the web to...
  29. C

    BRS: Using geodesic congruences and frame fields to compute optical experience

    I. Overview Another SA asked me to elaborate on a remark I made to the effect that frequency shift phenomena always (even in Minkowski vacuum) involve at least the following ingredients: two (proper time parameterized) timelike curves C, C' an event A on C ("emission event") an...
  30. F

    Kinetic energy, heat, and reference frame

    I'm having some trouble reconciling the following facts: 1) that kinetic energy depends on v _squared_, 2) at the same time energy is conserved in all reference frames, and 3) reference frames transform linearly in v in classical mechanics (galileo transform). I've basically been able to boil...
  31. T

    Frame - Frame Grabber and SimplePCI Compatibility for Microscope Imaging

    Has anyone used the Simple-PCI program to couple with the Meteor-II Digitcal PCI card for imaging from a commercial microscope like the Nikon Eclipse? Our version of the Simple-PCI does not recognise the frame grabber at all. Any help is appreciated. Ising
  32. B

    Causality violation from FTL signaling within the same reference frame only?

    I apologize if this has been asked before. I searched numerous times and couldn't find any discussion on this specific topic. Every description I've read of the impossibility of FTL signaling uses some variation of this diagram: http://www.theculture.org/rich/sharpblue/archives/000089.html...
  33. W

    Ball dropping and frame of reference

    Consider I am in the train with a ball traveling at normal speed of a train. I drop the ball, it follows a straight path of descent and falls in front of my feet. For an observer on the platform, the ball follows a parabolic path and falls in front of my feet. (Please go to this...
  34. stevmg

    Events can be simultaneous in one time frame but not so in others

    A recent forum thread went into a long disussion of simultaneity. The term "ansible line" was used (later referred to as a "simultaneity line.") Einstein demonstrated with a thought experiment with regards to lightning and a moving train that events can be simultaneous in one time frame but...
  35. P

    GR: Local Inertial Frame & Poincare Invariance

    Is it possible to deifine local inertial frame which is Poincare invariant (in general relativity) (every manifold is locally flat, so we can chose coordinates which are almost pseudoeuclidean, but in what sense they might be Poincare invariant) Thanks.
  36. S

    Exploring the Twin Paradox: Searching for the Oldest Frame of Reference

    I was just working on my knowledge of the twin paradox, and had a question that I couldn't find an answer to anywhere: If I understand it correctly the paradox is resolved because the two frames are not symmetrical, one is non-inertial, so that frame has it's clock run slower. So if you carry...
  37. D

    Why is the speed of light independent of a frame of reference?

    I understand the Michelson–Morley experiment and its result; but what I don't know yet is the REASON. Example: A torch in free space is moving at a velocity [v] w.r.t me. Considering the material nature of light, shouldn't the speed of photons emitted from the torch be [v+c] w.r.t ME? According...
  38. A

    Frame Independance of acceleration ?

    It seems clear that all inertial frames would agree that a frame was accelerating based on instantaneous (short interval) relative velocity measurements. That all frames would agree that the velocity was changing over time relative to their own frame but it is not so clear if they would all...
  39. J

    Elastic collisions in COM frame

    Homework Statement Consider an elastic collision of two particles in the centre of mass frame. Briefly explain why the speed of EACH particle after the collision is the same as before the collision. (FYI this is exam revision so it isn't worth any marks) The Attempt at a Solution...
  40. X

    How Does a Homogeneous Fluid Behave in a Rotating Cylinder?

    Here is the problem: (Question 5-2 in Binney&Tremaine Galactic Dynamics) Consider a homogeneous self-gravitating fluid of uniform density \rho_0 contained within a rotating cylinder of radius R_0. The cylinder and the fluid rotate at angular speed \Omega about the axis of the cylinder, which...
  41. C

    Special relativity: local frames versus global frame in a loop scenario

    Take the following setup: A series of pulses of radio signal is relayed around the world, along the equator. There is no "gap", it is a continuous loop along numerous relay stations build along the equator. The total number of pulses is fixed at 648,000 - I'll explain in a minute why that...
  42. Mentz114

    Obtaining the Metric in a Boosted Observer Frame?

    I'm trying to get a metric in the frame of a boosted observer. The spacetime in question has coframe and frame basis vectors \begin{align*} \vec{\sigma}^0 = \frac{-1}{\sqrt{F}}dt\ \ \ \ & \vec{e}_0 = -\sqrt{F}\partial_t \\ \vec{\sigma}^1 = \sqrt{F}dz\ \ \ \ & \vec{e}_1 =...
  43. I

    Thermal conductivity, pressed steel frame, insulated wall.

    Exterior commercial frames (.053") embedded in a concrete wall 8" thick with 3" layers of polystryrene (3# density) on each side of concrete cavity. Frame rests on foam inside and outside of building. Frame is grouted solid with poured in place concrete. Is there an appreciable (to be...
  44. M

    A non-inertial frame is non-inertial with respect to what?

    Considerer a closed box into space: • In constant acceleration. • Turning around its axis. Einstein used the first case as a thought experiment (http://galileo.phys.virginia.edu/classes/252/mass_and_energy.html) that led to the general theory of relativity: the occupant of the box could...
  45. jaketodd

    Does the graviton move at the speed of light in any reference frame?

    Does the graviton move at the speed of light in any reference frame? Thanks, Jake
  46. Z

    If velocity is subjective to an observers frame of reference?

    If velocity is subjective to an observers frame of reference, then isn't energy (kinetic) also subjective? How can we define energy as objective if it changes depending on your frame of reference?
  47. 9

    How to find energy value of this frame equilibrium?

    https://www.physicsforums.com/attachment.php?attachmentid=25852&d=1274225973 The A side, move down ward. The O is a pin, with no friction. The A and B have their own mass. The length of the stick or beam or frame is known. How to describe the energy of A down word until reach high h? i...
  48. 9

    How to find energy value of this frame equilibrium?

    http://3.bp.blogspot.com/_-kzA7K4dWrs/S_MNmOQpffI/AAAAAAAAAAU/NxUDhvbBw70/s1600/gambar+benda+momen.JPG" How to find energy value of this frame equilibrium? The A side, move down ward. The O is a pin, with no friction. The A and B have their own mass. The length of the stick or beam or frame...
  49. T

    Are particles frame independant?

    Could an observer in a gravity well perceive a particle to be a differnt type of particle than an obsever who is outside of the gravity well? Can an observer in one frame see a hydrogen atom and an observer in another frame see a neutron?
  50. P

    Tension of two strings/picture frame

    Homework Statement Hey guys and girls I have tried to solve this one but I got part (b) wrong any help would be awesome :) A picture hangs on the wall suspended by two strings, as shown in Figure 6-24, with θ = 72°. The tension in string 1 is 2.0 N there is a picture with two strings...
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