Demonstrating the first postulate of relativity in a lift

2021 ◽  
Vol 57 (1) ◽  
pp. 015021
Author(s):  
Stephen Hughes ◽  
Tim Croxford
Keyword(s):  
Reference Frames ◽  
Slow Motion ◽  
Inertial Mass ◽  
Vertical Acceleration ◽  
Speed Of Light ◽  
Height Difference ◽  
Motion Feature ◽  
Accelerometer Signal ◽  
Significant Difference ◽  
All Speeds

Abstract The first of the two postulates of relativity states that the laws of physics are the same in all inertial reference frames. Often it is assumed that the postulates are mainly concerned with objects moving at a significant fraction of the speed of light. However, the postulates are applicable at all speeds from a snail to a photon. To practically demonstrate the first postulate, the time for a ball to drop a known distance was measured in a stationary and moving lift. An accelerometer app on an iPhone 7 was used to measure the vertical acceleration while the lift travelled between floors and verified that the lift ascended and descended at a constant speed when the ball was dropped. The slow-motion feature of the iPhone 7 (240 fps) was used to capture videos of the falling ball. The number of frames for the ball to fall in a stationary, descending, and ascending lift was respectively 102.4 ± 0.55 , 102.3 ± 1.64 , 99.8 ± 4.21. A t-test revealed no significant difference between these values, confirming the validity of the first postulate. The accelerometer signal was integrated to estimate the average speed of the lift between the bottom and top floor, which was then used to estimate the height difference. An electronic balance placed on the floor of the lift was used to demonstrate the first postulate and the equivalence principle of General Relativity that states that gravitational and inertial mass are equivalent.

Interacting charges I

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Electromagnetic Interaction ◽  
Equations Of Motion ◽  
Inertial Mass ◽  
Dipole Approximation ◽  
Speed Of Light ◽  
Third Order ◽  
Mass System ◽  
Dipole Radiation ◽  
All Speeds ◽  
Theories Of Gravitation

This chapter addresses the problem of radiation by a system of point charges. Owing to the fact that the electromagnetic interaction propagates at finite speed, this problem can only be solved iteratively, by assuming that all speeds are small compared to the speed of light. The chapter then derives the dipole and quadrupole formulas giving the radiation field and the energy radiated by the system in the lowest orders. Finding the field and the radiation of a system of charges beyond the dipole approximation is rather more difficult, but necessary in the absence of dipole radiation. This is also a useful exercise for studying the radiation of a mass system in theories of gravitation where the gravitational mass is equal to the inertial mass. In addition, the chapter finds the equations of motion of the charges of the system to third order in the velocities.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

The Contact Diffusion of Linguistic Practices

2015 ◽  
Vol 5 (2) ◽  
pp. 169-201 ◽  
Author(s):  
Jürgen Bohnemeyer ◽  
Katharine T. Donelson ◽  
Randi E. Moore ◽  
Elena Benedicto ◽  
Alyson Eggleston ◽  
...  
Keyword(s):  
Language Contact ◽  
Language Use ◽  
Reference Frames ◽  
Indigenous Languages ◽  
Spatial Reference ◽  
Diffusion Analysis ◽  
Significant Difference ◽  
Education Levels ◽  
Spatial Reference Frame ◽  
Using Data

We examine the extent to which practices of language use may be diffused through language contact and areally shared, using data on spatial reference frame use by speakers of eight indigenous languages from in and around the Mesoamerican linguistic area and three varieties of Spanish. Regression models show that the frequency of L2-Spanish use by speakers of the indigenous languages predicts the use of relative reference frames in the L1 even when literacy and education levels are accounted for. A significant difference in frame use between the Mesoamerican and non-Mesoamerican indigenous languages further supports the contact diffusion analysis.

Understanding the difference in softness of Australian Soft Rolling Skin wool and conventional Merino wool

2021 ◽  
pp. 004051752110505
Author(s):  
Hao Yu ◽  
Christopher Hurren ◽  
Xin Liu ◽  
Xungai Wang
Keyword(s):  
Fiber Diameter ◽  
Purchasing Decisions ◽  
Key Factors ◽  
Height Difference ◽  
Moisture Regain ◽  
Merino Wool ◽  
Wool Fibers ◽  
Significant Difference ◽  
The Difference ◽  
Wool Industry

Softness is one of the key elements of textile comfort and is one of the main considerations when consumers make purchasing decisions. In the wool industry, softness can reflect the quality and value of wool fibers. There is verifiable difference in subjective softness between Australian Soft Rolling Skin (SRS) wool and conventional Merino (CM) wool, yet the key factors responsible for this difference are not yet well understood. Fiber attributes, such as crimp (curvature), scale morphology, ortho-to-cortex (OtC) ratio and moisture regain, may have a significant influence on softness performance. This study has examined these key factors for both SRS and CM wool and systematically compared the difference in these factors. There was no significant difference in the crimp frequency between these two wools; however, the curvature of SRS wool was lower than that of CM wool within the same fiber diameter ranges (below 14.5 micron, 16.5–18.5 micron). This difference might be caused by the lower OtC ratio for SRS wool (approximately 0.60) than for CM wool (approximately 0.66). The crystallinity of the two wools was similar and not affected by the change in OtC ratio. SRS wool has higher moisture regain than CM wool by approximately 2.5%, which could reduce the stiffness of wool fibers. The surface morphology for SRS wool was also different from that of CM wool. The lower cuticle scale height for SRS wool resulted in its smoother surface than CM wool. This cuticle height difference was present even when they both had similar cuticle scale frequency.

scholarly journals Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

2020 ◽  
Vol 4 ◽  
pp. 239821282093946
Author(s):  
Maneesh V. Kuruvilla ◽  
David I. G. Wilson ◽  
James A. Ainge
Keyword(s):  
Entorhinal Cortex ◽  
Reference Frames ◽  
Spatial Information ◽  
Unit Recording ◽  
Egocentric Reference Frame ◽  
Spatial Frames Of Reference ◽  
Significant Difference ◽  
Cue Processing ◽  
The Impact

During navigation, landmark processing is critical either for generating an allocentric-based cognitive map or in facilitating egocentric-based strategies. Increasing evidence from manipulation and single-unit recording studies has highlighted the role of the entorhinal cortex in processing landmarks. In particular, the lateral (LEC) and medial (MEC) sub-regions of the entorhinal cortex have been shown to attend to proximal and distal landmarks, respectively. Recent studies have identified a further dissociation in cue processing between the LEC and MEC based on spatial frames of reference. Neurons in the LEC preferentially encode egocentric cues while those in the MEC encode allocentric cues. In this study, we assessed the impact of disrupting the LEC on landmark-based spatial memory in both egocentric and allocentric reference frames. Animals that received excitotoxic lesions of the LEC were significantly impaired, relative to controls, on both egocentric and allocentric versions of an object–place association task. Notably, LEC lesioned animals performed at chance on the egocentric version but above chance on the allocentric version. There was no significant difference in performance between the two groups on an object recognition and spatial T-maze task. Taken together, these results indicate that the LEC plays a role in feature integration more broadly and in specifically processing spatial information within an egocentric reference frame.

scholarly journals Optimal Speed Control Humps Design Based on Driver Comfort

2021 ◽  
Vol 18 (3) ◽  
pp. 8941-8958
Author(s):  
Hamid Gheibollahi ◽  
Masoud Masih-Tehrani
Keyword(s):  
Genetic Algorithm ◽  
Optimal Design ◽  
Speed Control ◽  
Vertical Acceleration ◽  
Mean Square ◽  
Horizontal Acceleration ◽  
Car Suspension ◽  
Different Types ◽  
Occupant Comfort ◽  
All Speeds

The purpose of this study is to optimise the different speed control humps by considering the vertical and horizontal acceleration of the driver’s head. In previous researches, the main focus was only on vertical acceleration, but in this study, horizontal acceleration of the head is also considered. Here, the root mean square (RMS) of acceleration of head is considered as a measure of occupant comfort. The modelling is performed by a non-linear half-car suspension system (4-DOF) with a linear model of a driver (10-DOF) and a seat. The hamps under study are circular, sinusoidal, half-sinusoidal, and trapezoidal. Finally, by analysing the results, the optimal design of each type of hump is performed. The objective function used is a combination of horizontal and vertical acceleration which is performed using MATLAB genetic algorithm. The results show a significant reduction in horizontal and vertical acceleration at all speeds. From this modelling, it is possible to extract a suitable range for passing the speed of cars over different types of humps. In this study, it is shown that the acceleration values for the circular and half-sinusoidal humps at all speeds are quite close to each other.

ON THE RELATIVISTIC THEORY OF CHARGE

1993 ◽  
Vol 07 (06) ◽  
pp. 413-419
Author(s):  
Y. AKTAS ◽  
M. W. EVANS ◽  
F. FARAHI
Keyword(s):  
Electromagnetic Field ◽  
Experimental Observation ◽  
Linear Relation ◽  
Relativistic Theory ◽  
Qualitative Agreement ◽  
Point Charge ◽  
Reference Frames ◽  
Speed Of Light ◽  
Scalar Parameter ◽  
Vector Potentials

The concept of charge is developed relativistically by assuming that there is a linear relation between point charge (e) and point mass (m) of the type: [Formula: see text] where ζ is a scalar parameter which is unchanged in all reference frames. The theory shows that charge, in a relativistic development based on this hypothesis, depends in general on the velocity of the particle carrying the charge, and the latter vanishes at the speed of light. The hypothesis (1) also implies that charge depends on the scalar and vector potentials of the electromagnetic field. These conclusions are in qualitative agreement with experimental observation.

scholarly journals Comparative Analysis of Change between Ellipsoidal Height Differences and Equivalent Orthometric Height Difference

2020 ◽  
Vol 12 (1) ◽  
pp. 132-144
Author(s):  
Tata Herbert ◽  
Raufu Ibrahim Olatunji
Keyword(s):  
Comparative Analysis ◽  
Global Positioning System ◽  
Orthometric Height ◽  
Ellipsoidal Height ◽  
Height Difference ◽  
Significant Difference ◽  
Global Positioning ◽  
Analysis Of Change ◽  
Automatic Level

Height is an important component in the determination of the position of a point. The study aimed at performing a comparative analysis of change between ellipsoidal height differences and the equivalent orthometric height difference of points. A hi-target Differential Global Positioning System (DGPS) was used to acquire GPS data with an occupation period of thirty (30) minutes on each point, which were processed using Hi-target Geomatics Office (HGO) software to obtain the ellipsoidal heights. An automatic level instrument was used to acquire leveling data, which were processed using the height of collimation method to obtain the orthometric heights. A total of fifty (50) points were occupied as common points for both the GPS and levelling observations at 20-meter intervals. The accuracy of the height difference was determined using standard deviation with the ellipsoidal height difference as 53.59cm and the orthometric height as 53.07cm respectively. A Root Mean Square Error value of 0.0621m was obtained as the accuracy of the change between the two height differences. Statistical analysis using the independent-sample Z test was used to analyze the data at a 5% significant level. The result shows no significant difference in the performance of the two height systems. It is worthy to note that GPS and spirit levelling height differences can be used interchangeably for any heighting in short distances for surveying and engineering applications.

scholarly journals Spatial variation of fundamental constants: Testing models with thermonuclear supernovae

2018 ◽  
Vol 27 (09) ◽  
pp. 1850099 ◽  
Author(s):  
C. Negrelli ◽  
L. Kraiselburd ◽  
S. Landau ◽  
E. García-Berro
Keyword(s):  
Spatial Variation ◽  
Fundamental Constant ◽  
Dipole Model ◽  
Type Ia Supernovae ◽  
Fundamental Constants ◽  
Speed Of Light ◽  
Significant Difference ◽  
Type Ia ◽  
Ia Supernovae ◽  
Peak Luminosity

Since Dirac stated his Large Number Hypothesis the space-time variation of fundamental constants has been an active subject of research. Here we analyze the possible spatial variation of two fundamental constants: the fine structure constant [Formula: see text] and the speed of light [Formula: see text]. We study the effects of such variations on the luminosity distance and on the peak luminosity of Type Ia supernovae (SNe Ia). For this, we consider the change of each fundamental constant separately and discuss a dipole model for its variation. Elaborating upon our previous work, we take into account the variation of the peak luminosity of Type Ia supernovae resulting from the variation of each of these fundamental constants. Furthermore, we also include the change of the energy release during the explosion, which was not studied before in the literature. We perform a statistical analysis to compare the predictions of the dipole model for [Formula: see text] and [Formula: see text] variation with the Union 2.1 and JLA compilations of SNe Ia. Allowing the nuisance parameters of the distance estimator [Formula: see text] and the cosmological density matter [Formula: see text] to vary. As a result of our analysis, we obtain a first estimate of the possible spatial variation of the speed of light [Formula: see text]. On the other hand, we find that there is no significant difference between the several phenomenological models studied here and the standard cosmological model, in which fundamental constants do not vary at all. Thus, we conclude that the actual set of data of Type Ia supernovae does not allow to verify the hypothetical spatial variation of fundamental constants.

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