Comment on: Curling rock dynamics - The motion of a curling rock: inertial vs. noninertial reference frames

2000 ◽  
Vol 77 (11) ◽  
pp. 903-922 ◽  
Author(s):  
MRA Shegelski ◽  
M Reid

We examine the approach used and the results presented in a recent publication(Can. J. Phys. 76, 295 (1998))in which (i) a noninertial reference frame is used to examine the motion ofa curling rock, and (ii) the lateral motion of a curling rock isattributed to left-right asymmetry in the force acting on the rock.We point out the important differences between describing the motionin an inertial frame as opposed to a noninertial frame.We show that a force exhibiting left-right asymmetryin an inertial frame cannot explain the lateral motion of a curlingrock. We also examine, as was apparently done in the recent publication,an effective force that has left-right asymmetry in a noninertial, rotating frame. We show that such a force is not left-right asymmetric in an inertial frame, and that anylateral motion of a curling rock attributed to the effective forcein the noninertial frame is actually due to a real force, in aninertial frame, which has a net nonzero component transverse to the velocityof the center of mass. We inquire as to the physical basis for thetransverse component of this real force. We also examine the motion ofa rotating cylinder sliding over a smooth surface for which there isno melting: we show that the motion is easily analyzed in an inertialframe and that there is little to be gained by considering a rotating frame.We relate the results for this simple case to the more involved problemof the motion of a curling rock: we find that the motion of curling rocksis best studied in inertial frames. Perhaps most importantly, we showthat the approach taken and the results presented in the recent publicationlead to predicted motions of curling rocks that are indisagreement with observed motions of real curling rocks.PACS Nos.: 46.00, 01.80+b

1986 ◽  
Vol 7 ◽  
pp. 101-102
Author(s):  
C A Murray

Astrometry can be defined as the measurement of space-time coordinates of photon events. For example, in principle, in classical optical astrometry, we measure the components of velocity, and hence the direction, of an incoming photon with respect to an instrumental coordinate system, and the clock time, at the instant of detection. The observer’s coordinate system at any instant can be identified with a local inertial frame. In the case of interferometric observations, the measurements are of clock times of arrival of a wavefront at two detectors whose spatial coordinates are specified with respect to instantaneous inertial frames.


2021 ◽  
Vol 34 (3) ◽  
pp. 274-278
Author(s):  
Reiner Georg Ziefle

On Earth, we always measure the constant velocity c of electromagnetic radiation. Einstein assumed the velocity c of light to be constant in all inertial frames and developed his theory of special relativity by considering a light beam that moves back and forth, whereby he derived transformations between the coordinates of two reference frames: A moving reference frame represented by the coordinate system k and the coordinate system k that is at rest with respect to k. However, by applying Einstein’s theory of relativity, with its postulates of relativistic time dilation and length contraction, to electromagnetic radiation that moves only in one direction, either in the direction of or in the opposite direction to a moving inertial frame, it is demonstrated that the constancy of the velocity c of light is not compatible with Einstein’s theory of special relativity. It becomes obvious that Einstein’s relativistic physics must be an unrealistic theory, and consequently, we need an alternative, nonrelativistic, explanation of the constancy of the velocity c of electromagnetic radiation measured on Earth, and for the special and general “relativistic” phenomena.


2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Emre Dil ◽  
Talha Zafer

We know that the Lorentz transformations are special relativistic coordinate transformations between inertial frames. What happens if we would like to find the coordinate transformations between noninertial reference frames? Noninertial frames are known to be accelerated frames with respect to an inertial frame. Therefore these should be considered in the framework of general relativity or its modified versions. We assume that the inertial frames are flat space-times and noninertial frames are curved space-times; then we investigate the deformation and coordinate transformation groups between a flat space-time and a curved space-time which is curved by a Schwarzschild-type black hole, in the framework of f(R) gravity. We firstly study the deformation transformation groups by relating the metrics of the flat and curved space-times in spherical coordinates; after the deformation transformations we concentrate on the coordinate transformations. Later on, we investigate the same deformation and coordinate transformations in Cartesian coordinates. Finally we obtain two different sets of transformation groups for the spherical and Cartesian coordinates.


2000 ◽  
Vol 77 (11) ◽  
pp. 847-862 ◽  
Author(s):  
MRA Shegelski ◽  
M Reid ◽  
R Niebergall

We consider the motion of a cylinder with the same mass and sizeas a curling rock, but with a very different contact geometry.Whereas the contact area of a curling rock is a thin annulus havinga radius of 6.25 cm and width of about 4 mm, the contact area of the cylinderinvestigated takes the form of several linear segments regularly spacedaround the outer edge of the cylinder, directed radially outward from the center,with length 2 cm and width 4 mm. We consider the motion of this cylinderas it rotates and slides over ice having the nature of the ice surfaceused in the sport of curling. We have previously presented a physicalmodel that accounts for the motion of curling rocks; we extend this modelto explain the motion of the cylinder under investigation. In particular,we focus on slow rotation, i.e., the rotational speed of the contact areasof the cylinder about the center of mass is small compared to thetranslational speed of the center of mass.The principal features of the model are (i) that the kineticfriction induces melting of the ice, with the consequence that thereexists a thin film of liquid water lying between the contact areasof the cylinder and the ice; (ii) that the radial segmentsdrag some of the thin liquid film around the cylinder as it rotates,with the consequence that the relative velocity between the cylinderand the thin liquid film is significantly different than the relativevelocity between the cylinder and the underlying solid ice surface.Since it is the former relative velocity that dictates the nature of themotion of the cylinder, our model predicts, and observations confirm, thatsuch a slowly rotating cylinder stops rotating well before translationalmotion ceases. This is in sharp contrast to the usual case of most slowlyrotating cylinders, where both rotational and translational motion ceaseat the same instant. We have verified this prediction of our model bycareful comparison to the actual motion of a cylinder having a contactarea as described.PACS Nos.: 46.00, 01.80+b


2014 ◽  
Vol 29 (29) ◽  
pp. 1450163 ◽  
Author(s):  
Horace W. Crater ◽  
Luca Lusanna

We make a critical comparison of relativistic and nonrelativistic classical and quantum mechanics of particles in inertial frames as well of the open problems in particle localization at both levels. The solution of the problems of the relativistic center-of-mass, of the clock synchronization convention needed to define relativistic 3-spaces and of the elimination of the relative times in the relativistic bound states leads to a description with a decoupled nonlocal (nonmeasurable) relativistic center-of-mass and with only relative variables for the particles (single particle subsystems do not exist). We analyze the implications for entanglement of this relativistic spatial nonseparability not existing in nonrelativistic entanglement. Then, we try to reconcile the two visions showing that also at the nonrelativistic level in real experiments only relative variables are measured with their directions determined by the effective mean classical trajectories of particle beams present in the experiment. The existing results about the nonrelativistic and relativistic localization of particles and atoms support the view that detectors only identify effective particles following this type of trajectories: these objects are the phenomenological emergent aspect of the notion of particle defined by means of the Fock spaces of quantum field theory.


Author(s):  
P. J. E. Peebles

This chapter discusses the development of physical sciences in seemingly chaotic ways, by paths that are at best dimly seen at the time. It refers to the history of ideas as an important part of any science, and particularly worth examining in cosmology, where the subject has evolved over several generations. It also examines the puzzle of inertia, which traces the connection to Albert Einstein's bold idea that the universe is homogeneous in the large-scale average called “cosmological principle.” The chapter cites Newtonian mechanics that defines a set of preferred motions in space, the inertial reference frames, by the condition that a freely moving body has a constant velocity. It talks about Ernst Mach, who argued that inertial frames are determined relative to the motion of the rest of the matter in the universe.


1990 ◽  
Vol 141 ◽  
pp. 111-114
Author(s):  
A. V. Voinov

The astonomical consequences of recently developed theoretical methods of relativistic astrometry are discussed. The set of practically important reference systems is described. These reference systems generalize the locally inertial frames of general relativistic test observer, the hierarchy of Jacoby coordinates for dynamical problems and the dynamically inertial reference systems of fundamental astrometry. In practical application of this formalism much attention is paid for relativistic transformation functions relating the ∗∗ecliptical coordinates corresponding to the baryecnters of the Solar system, the Earth-Moon subsystem and the Earth. Solutions to several kinds of relativistic precession are also presented.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chang-Kang Hu ◽  
Jin-Ming Cui ◽  
Alan C. Santos ◽  
Yun-Feng Huang ◽  
Chuan-Feng Li ◽  
...  

AbstractValidity conditions for the adiabatic approximation are useful tools to understand and predict the quantum dynamics. Remarkably, the resonance phenomenon in oscillating quantum systems has challenged the adiabatic theorem. In this scenario, inconsistencies in the application of quantitative adiabatic conditions have led to a sequence of new approaches for adiabaticity. Here, by adopting a different strategy, we introduce a validation mechanism for the adiabatic approximation by driving the quantum system to a non-inertial reference frame. More specifically, we begin by considering several relevant adiabatic approximation conditions previously derived and show that all of them fail by introducing a suitable oscillating Hamiltonian for a single quantum bit (qubit). Then, by evaluating the adiabatic condition in a rotated non-inertial frame, we show that all of these conditions, including the standard adiabatic condition, can correctly describe the adiabatic dynamics in the original frame, either far from resonance or at a resonant point. Moreover, we prove that this validation mechanism can be extended for general multi-particle quantum systems, establishing the conditions for the equivalence of the adiabatic behavior as described in inertial or non-inertial frames. In order to experimentally investigate our method, we consider a hyperfine qubit through a single trapped Ytterbium ion 171Yb+, where the ion hyperfine energy levels are used as degrees of freedom of a two-level system. By monitoring the quantum evolution, we explicitly show the consistency of the adiabatic conditions in the non-inertial frame.


2015 ◽  
Vol 93 (5) ◽  
pp. 503-518 ◽  
Author(s):  
Alexander L. Kholmetskii ◽  
Tolga Yarman

We continue the analysis of Thomas–Wigner rotation (TWR) and Thomas precession (TP) initiated in (Kholmetskii and Yarman. Can. J. Phys. 92, 1232 (2014). doi:10.1139/cjp-2014-0015 ; Kholmetskii et al. Can. J. Phys. 92, 1380 (2014). doi:10.1139/cjp-2014-0140 ), where a number of points of serious inconsistency have been found in the relativistic explanation of these effects. These findings motivated us to address covariant ether theories (CET), as suggested by the first author (Kholmetskii. Phys. Scr. 67, 381 (2003)) and to show that both TWR and TP find a perfect explanation in CET. We briefly reproduce the main points of CET, which are constructed on the basis of general symmetries of empty space–time, general relativity principles, and classical causality, instead of Einstein’s postulates of the special theory of relativity (STR). We demonstrate that with respect to all known relativistic experiments performed to date in all areas of physics, both theories, STR and CET, yield identical results. We further show that the only effect that differentiates STR and CET is the measurement of time-dependent TWR of two inertial frames, K1 and K2, related by the rotation-free Lorentz transformation with a third inertial frame, K0, in the situation, where the relative velocity between K1 and K2 remains fixed. We discuss the results obtained and suggest a novel experiment, which can be classified as a new crucial test of STR.


1981 ◽  
Vol 63 ◽  
pp. 268-280
Author(s):  
J. Kovalevsky

AbstractThe very great accuracy with which the motions of the Moon can now be monitored by laser ranging, differential VLBI and occultation observations, implies that the interpretation of the measurements is conditioned by the choice and the accurate knowledge of a selenocentric, a terrestrial and a celestial frames. Two different types of selenocentric reference frames can be envisioned. The present selenographic frames are discussed but the author proposes that one should introduce a system defined by a purely geometric means. Some consequences of such a choice are discussed. One feature of the future conventional terrestrial frame is very important for Earth-Moon dynamics. Its origin should coincide with the center of mass of the Earth as determined by lunar laser ranging. As far as the quasi-inertial reference systems are concerned, the liaisons between a purely lunar dynamical system, subject to some hardly modelable effects, and purely celestial systems are analysed. The reduction of observations made with various techniques implies the use of different systems, and several problems are stated that should be solved before a unique system for Earth-Moon dynamics might be used.


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