scholarly journals The Physical Nature of Velocity

2018 ◽  
Vol 10 (6) ◽  
pp. 15
Author(s):  
Zhonggang Li
Keyword(s):  
Mathematical Model ◽  
Total Mass ◽  
Maximum Velocity ◽  
Physical Nature ◽  
Added Mass ◽  
Basic Unit ◽  
Significant Difference ◽  
Moving Body ◽  
Basic Particle ◽  
The Universe

Matter and energy are made up of the same basic particles. Why, then, is there a significant difference between matter and energy? This is because their basic particle compositions differ. The basic particle is the basic unit of mass and energy. Mass and energy conservations are essentially basic particle conversions. The basic particle is a vector, moving at the maximum velocity of the universe; however, after a substance tangibly solidifies, this velocity becomes zero. The velocity of a moving object is, thus, the ratio between the basic particles contributing to energy and those contributing to mass, and the direction of its velocity is determined by the basic particle directions. Electrons, photons, neutrons, protons, neutrinos, and other microscopic particles consist of basic particles. The total mass of a moving body increases with increasing velocity. This added mass is composed of basic particles provided by an external system. As relativity is a mathematical model, its equations may satisfy mathematical principles even though some of them may not represent objective physical facts; instead, these may simply be mathematical solutions without physical meanings.

scholarly journals DARK MATTER DYNAMICS AND INDIRECT DETECTION

2005 ◽  
Vol 20 (14) ◽  
pp. 1021-1036 ◽  
Author(s):  
GIANFRANCO BERTONE ◽  
DAVID MERRITT
Keyword(s):  
Dark Matter ◽  
Total Mass ◽  
Galactic Center ◽  
Direct Detection ◽  
Indirect Detection ◽  
Matter Distribution ◽  
Dark Matter Distribution ◽  
Particle Dark Matter ◽  
The Universe ◽  
Rule Out

Non-baryonic, or "dark", matter is believed to be a major component of the total mass budget of the Universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter particles with laboratory detectors) and indirect detection (via observations of the products of dark matter self-annihilations), focusing in particular on the Galactic center, which is among the most promising targets for indirect detection studies. The gravitational potential at the Galactic center is dominated by stars and by the supermassive black hole, and the dark matter distribution is expected to evolve on sub-parsec scales due to interaction with these components. We discuss the dominant interaction mechanisms and show how they can be used to rule out certain extreme models for the dark matter distribution, thus increasing the information that can be gleaned from indirect detection searches.

scholarly journals Dynamics Analysis of a Mathematical Model for New Product Innovation Diffusion

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Chunru Li ◽  
Zujun Ma
Keyword(s):  
Mathematical Model ◽  
Time Delay ◽  
Media Coverage ◽  
New Product ◽  
Normal Form Theory ◽  
Center Manifold Theorem ◽  
Significant Difference ◽  
Form Theory ◽  
The Difference ◽  
The Stability

In this paper, a mathematical model with time-delay-related parameters and media coverage to describe the diffusion process of new products is proposed, in which the time-delay-related parameters denote the stage in which potential customers decide whether to adopt a new product. Then, the stability and the Hopf bifurcation of the proposed model are analyzed in detail. The center manifold theorem and the normal form theory are used to investigate the stability of the bifurcating periodic solution. Moreover, a numerical simulation is conducted to investigate the difference between the model with delay-dependent parameters and that with delay-independent parameters. The results show that there is significant difference between the two models.

scholarly journals Generalized F(R, T) cosmological models with fermionic fields

2021 ◽  
Vol 2090 (1) ◽  
pp. 012063
Author(s):  
Koblandy Yerzhanov ◽  
Gulnur Bauyrzhan ◽  
Ratbay Myrzakulov
Keyword(s):  
Mathematical Model ◽  
Cosmological Model ◽  
Main Idea ◽  
Scale Factor ◽  
Specific Form ◽  
Fermion Field ◽  
Fermionic Fields ◽  
Particular Solution ◽  
The Universe ◽  
Symmetry Method

Abstract We investigated the gravity model F (R, T), which interacts with a fermion field in a uniform and isotropic at spacetime FLRW. The main idea and purpose of the work donewas to create a mathematical model and find a particular solution for the scale factor a, since it describes the dynamics of the evolution of the Universe. The solutions for this universe are obtained using the Noether symmetry method. With its help, a specific form of the Lagrangian is obtained. And the possible types of the scale factor were found. The evolution of the resulting cosmological model has been investigated.

scholarly journals Bondgraph modelling and simulation of the dynamic behaviour of above-knee prostheses

1987 ◽  
Vol 11 (2) ◽  
pp. 65-70 ◽  
Author(s):  
P. G. Van De Veen ◽  
W. Van Der Tempel ◽  
J. De Vreiss
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Mass Distribution ◽  
Total Mass ◽  
Dynamic Behaviour ◽  
Step Length ◽  
Swing Phase ◽  
Knee Prostheses ◽  
Prosthetic Foot ◽  
Walking Velocity

A mathematical model was used to investigate the dynamic behaviour of an above-knee (AK) prosthesis in the swing phase and to analyse the influence of mass and mass distribution on the maximal stump load and the required energy. The model consists of a bondgraph model of the prosthesis and a “walking” model which predicts the walking velocity, step length and the femoral trajectory. Equipment was developed to measure the inertial properties of the components of the prosthesis. Through computer simulation, stickdiagrams of the swing phase and graphs of the variation with time of the hip and stump forces were obtained. It was found that for a normal AK prosthesis with a knee-lock mechanism the axial stump load is greatest at the beginning and at the end of the swing phase. At a walking velocity of 5 km/hr the maximum axial stump load amounts to 2.1 times the static weight of the prosthesis. The maximum axial stump force appeared to be almost directly proportional to the total mass of the prosthesis but independent of the mass distribution. The required energy also increased with the mass of the prosthesis but is' dependent on mass distribution. Because of their comparable weights the influence of the shoe is almost equal to the influence of the prosthetic foot. Thus lightweight shoes should be used with lightweight prosthetic feet in order to add to their advantages.

The Effects of Taping on Muscle Activity and Throwing Velocity in Fatigued Baseball Players

2021 ◽  
Vol 3 (1) ◽  
pp. 18-29
Author(s):  
Kara-Lyn R. Harrison ◽  
Paolo Sanzo ◽  
Carlos Zerpa ◽  
Taryn Klarner
Keyword(s):  
Pilot Study ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Performance Enhancement ◽  
Maximum Velocity ◽  
Baseball Players ◽  
Kinesio Tape ◽  
Significant Difference ◽  
Post Test ◽  
And Performance

Due to the repetitive high forces and torques placed on an individual during a baseball pitch, shoulder pain is present in 46-57% of pitchers. Therapeutic taping has been proposed to have beneficial qualities in injury prevention, rehabilitation, and performance enhancement via muscular facilitation. Therefore, the purpose of this pilot study was to investigate the effect of taping on the velocity of an overhead baseball throw and muscle activation patterning of the supraspinatus, infraspinatus, and pectoralis major muscles in baseball players after muscle fatigue was induced. Participants were asked to complete three pre-test maximum velocity overhead throws, a fatiguing protocol, followed by three post-test maximum velocity pitches. There was no statistically significant difference in throwing velocity or muscle activity with the application of the different taping conditions in the three phases of an overhead baseball throw. These finding suggest Kinesio Tape® does not change muscle activation or velocity of overhead baseball throws when compared to a no tape condition.

General Relativity and Cosmology

2020 ◽  
pp. 227-360
Author(s):  
P. J. E. Peebles
Keyword(s):  
Constant Velocity ◽  
Large Scale ◽  
Reference Frames ◽  
Physical Sciences ◽  
Inertial Frames ◽  
Moving Body ◽  
History Of ◽  
The Subject ◽  
Freely Moving ◽  
The Universe

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.

scholarly journals Deflection of light and shadow cast by a dual-charged stringy black hole

2020 ◽  
Vol 35 (28) ◽  
pp. 2050177
Author(s):  
Shubham Kala ◽  
Saurabh ◽  
Hemwati Nandan ◽  
Prateek Sharma
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Compact Object ◽  
Physical Nature ◽  
Space Time ◽  
Deflection Of Light ◽  
Shadow Cast ◽  
Light And Shadow ◽  
The Impact ◽  
The Universe

Gravitational lensing and black hole shadows are one of the strongest observational evidences to prove the existence of black holes in the universe. The gravitational lensing arises due to the deflection of light by the gravitational field of a gravitating body such as a black hole. Investigation of the shadow cast by a compact object as well as deflection of light around it may provide the useful information about physical nature of the particular compact object and other related aspects. In this paper, we study the deflection of light by a dual-charged stringy black hole space–time derived in dilaton-Maxwell gravity. The variation of deflection angle with the impact parameter for different values of electric and magnetic charges is studied. We also study the shadow of this black hole space–time to obtain the radius of shadow cast by it. We have considered an optically thin emission disk around it and observed that there are not significant changes in the shadow cast by this black hole compared to well-known Schwarzschild black hole space–time in GR.

scholarly journals Interaction Between Age and Change in Velocity During a Baseball Training Program

2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092793
Author(s):  
Christopher Antonacci ◽  
Thomas R. Atlee ◽  
Peter N. Chalmers ◽  
Christopher Hadley ◽  
Meghan E. Bishop ◽  
...  
Keyword(s):  
Training Program ◽  
Age Groups ◽  
Maximum Velocity ◽  
Age Group ◽  
Significant Difference ◽  
Group 3 ◽  
Baseball Pitchers ◽  
Group 2 ◽  
The Relationship ◽  
Group 1

Background: Pitching velocity is one of the most important metrics used to evaluate a baseball pitcher’s effectiveness. The relationship between age and pitching velocity after a lighter ball baseball training program has not been determined. Purpose/Hypothesis: The purpose of this study was to examine the relationship between age and pitching velocity after a lighter ball baseball training program. We hypothesized that pitching velocity would significantly increase in all adolescent age groups after a lighter baseball training program, without a significant difference in magnitude of increase based on age. Study Design: Cohort study; Level of evidence, 2. Methods: Baseball pitchers aged 10 to 17 years who completed a 15-week training program focused on pitching mechanics and velocity improvement were included in this study. Pitchers were split into 3 groups based on age (group 1, 10-12 years; group 2, 13-14 years; group 3, 15-17 years), and each group trained independently. Pitch velocity was assessed at 4 time points (sessions 3, 10, 17, and 25). Mean, maximum, and mean change in pitch velocity between sessions were compared by age group. Results: A total of 32 male baseball pitchers were included in the analysis. Mean/maximum velocity increased in all 3 age groups: 3.4/4.8 mph in group 1, 5.3/5.5 mph in group 2, and 5.3/5.2 mph in group 3. While mean percentage change in pitch velocity increased in all 3 age groups (group 1, 6.5%; group 2, 8.3%; group 3, 7.6%), the magnitude of change was not significantly different among age groups. Program session number had a significant effect on mean and maximum velocity, with higher mean and maximum velocity seen at later sessions in the training program ( P = .018). There was no interaction between age and program session within either mean or maximum velocity ( P = .316 and .572, respectively). Conclusion: Age had no significant effect on the magnitude of increase in maximum or mean baseball pitch velocity during a velocity and mechanics training program in adolescent males.

scholarly journals Investigating the Influence of Shaft Balance Point on Clubhead Speed: A Simulation Study

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 156
Author(s):  
William McNally ◽  
John McPhee
Keyword(s):  
Total Mass ◽  
Center Of Mass ◽  
Golf Club ◽  
Physical Interaction ◽  
Balance Point ◽  
Mass Distributions ◽  
Biomechanical Models ◽  
Significant Difference ◽  
The Mean ◽  
Simulation Results

In this study, a dynamic golfer model was used to investigate the influence of the golf shaft’s balance point (i.e., center of mass) on the generation of clubhead speed. Three hypothetical shaft designs having different mass distributions, but the same total mass and stiffness, were proposed. The golfer model was then stochastically optimized 100 times using each shaft. A statistically significant difference was found between the mean clubhead speeds at impact (p < 0.001), where the clubhead speed increased as the balance point moved closer to the grip. When comparing the two shafts with the largest difference in balance point, a 1.6% increase in mean clubhead speed was observed for a change in balance point of 18.8 cm. The simulation results have implications for shaft design and demonstrate the usefulness of biomechanical models for capturing the complex physical interaction between the golfer and golf club.

Determinism, Predictions, and Probabilism

2021 ◽  
pp. 85-88
Author(s):  
Francois Dépelteau
Keyword(s):  
Social Sciences ◽  
Natural Phenomena ◽  
Social Scientists ◽  
Social Phenomena ◽  
Biological Determinism ◽  
The Social ◽  
Significant Difference ◽  
Social Cause ◽  
Social Causes ◽  
The Universe

This chapter addresses determinism, which has been the predominant mode of perceiving the universe in modern sciences. The basic assumption is that any event is the effect of an external cause. Generally speaking, biological determinism focuses on the biological causes of events, whereas social sciences focus on the social causes. This mode of perceiving the social universe is typically associated with positivism and, more specifically, social naturalism — or the idea that there is no significant difference between social phenomena and natural phenomena. In this logic, it is assumed that social scientists can and should discover ‘social laws’ — or universal relations of causality between a social cause and a social effect. However, determinism in the social sciences has been criticized since its very beginning. In response to these critiques, many social scientists have adopted various forms of ‘soft’ determinism. The chapter then considers social predictions and probabilism.

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