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arXiv2013

Free Instrument for Movement Measure

This paper presents the validation of a computational tool that serves to obtain continuous measurements of moving objects. The software uses techniques of computer vision, pattern recognition and optical flow, to enable tracking of objects in videos, generating data trajectory, velocity, acceleration and angular movement. The program was applied to track a ball around a simple pendulum. The methodology used to validate it, taking as a basis to compare the values measured by the program, as well as the theoretical values expected according to the model of a simple pendulum. The experiment is appropriate to the method because it was built within the limits of the linear harmonic oscillator and energy losses due to friction had been minimized, making it the most ideal possible. The results indicate that the tool is sensitive and accurate. Deviations of less than a millimeter to the extent of the trajectory, ensures the applicability of the software on physics, whether in research or in teaching topics.

physics.ins-det↗
arXiv2013

Astronomical orientations in sanctuaries of Daunia

Prehistoric sanctuaries of Daunia date back several thousand years. During the Neolithic and Bronze Age the farmers in that region dug hypogea and holes whose characteristics suggest a ritual use. In the present note we summarize the results of the astronomical analysis of the orientation of the row holes in three different sites, and we point out the possible use of the setting of the stars of Centaurus. An interesting archaeological confirmation of an archaeoastronomical prediction is also reported.

physics.hist-ph↗
arXiv2013

An Observation of a Circular Motion using Ordinary Appliances: Train Toy, Digital Camera, and Android based Smartphone

Using a digital camera (Sony DSC-S75) in its video mode and a smartphone (Samsung GT-N700) equipped with an acceleration sensor, observation of a uniform circular motion of a toy train (Thomas & Friends, Player World, CCF No. 2277-13) is conducted. From the first observation average centripetal acceleration about 0.154 m/s2 is obtained, while the second gives 0.350 m/s2 of average centripetal acceleration by assuming ideal condition, where measured accelerations in z direction is not interpreted.

physics.pop-ph↗
arXiv2013

Macro photography with a tablet: applications on Science Teaching

In this work we present a simple way to get Macro photography (enlarged photographs) using a tablet or phone. We initially discuss the technique, which is essentially the accommodation of a drop of water on the camera lens. Next, we explore some applications to science teaching in primary and secondary levels. As discussed in the text, the simplicity and power of the technique may make it a good teaching tool for use in various disciplines such as Science, Biology and Physics.

physics.pop-ph↗
arXiv2013

Synchronous motion in a devil's stick -- variation on a theme by Kapitza

The counter-intuitive rotational motion of the propeller of a devil's stick when the agitator is rubbed against the pylon has long intrigued performers, audiences and scientists. The apparently unrelated phenomenon of self-stabilization of a Kapitza pendulum at the inverted position, once again an amazing lecture demonstration, has on the other hand been subjected to years of investigation and research. Here we show that the two systems are in fact identical, and obtain a previously unreported, friction-stabilized synchronously rotating state in the Kapitza pendulum, which in fact explains the rotational motion of the Devil's stick.

nlin.CD↗
arXiv2013

Judo match analysis,a powerful coaching tool, basic and advanced tools

In this second paper on match analysis, we analyze in deep the competition steps showing the evolution of this tool at National Federation level.On the basis of our,first classification. Furthermore, it is the most important source of technical assessment. Studying competition with this tool is essential for the coaches because they can obtain useful information for their coaching. Match Analysis is today the master key in situation sports like Judo, to help in useful way the difficult task of coach or best for National or Olympic coaching equips. In this paper it is presented a deeper study of the judo competitions at high level both from the male and female point of view, explaining at light of biomechanics, not only the throws evolution in time, introduction of Innovative and Chaotic techniques, but also the evolution of fighting style in these high level competitions, both connected with the grow of this Olympic Sport in the Word Arena. It is shown how new interesting ways are opened by this powerful coaching tool, very useful for National team technical management.In the last part of this paper we analyze advanced mathematical tools describing Couple of Athletes motion as Fractal Poisson Point Processes based on Fractional Brownian Motion to show how strategic evaluation, probability and short term forecast can be applied to Judo competition.

physics.pop-ph↗
arXiv2013

Techniques frequently used during London Olympic judo tournaments: a biomechanical approach

Feedback between training and competition should be considered in athletic training.The aim of the study was contemporary coaching tendencies in women s and men s judo with particular focus on a biomechanical classification of throws and grappling actions. Throwing technique frequencies grouped in the seven biomechanical classes were dependent on gender. A significant difference was found between frequencies of variable arm of physical lever technique scored by males and females as compared to the techniques counts. Significant differences between men who competed in extra lightweight and heavy weight concerned the frequency of the techniques used with maximum arm or variable arm of physical lever and a couple of forces applied by trunk and legs.In females a tendency to higher frequency of techniques that used couple of forces applied by arm or arms and leg was observed in extra lightweight compared to the heavy weight. Because the technique preferred in the fight depends on a gender and weight category of a judoka, the relationships found in this study, which can be justified by the biomechanics of throws, should be taken into consideration in technical and tactical coaching of the contestants. A method used in this study can be recommended for future research concerning coaching tendencies

physics.pop-ph↗
arXiv2013

Napoli Tokyo Napoli

This is a Magistralis Lectio held in Naples the October 28 2010, at 150 anniversary of Birth of Jigoro Kano Judo Founding Father, on Judo History, History of Biomechanics and Judo biomechanics. IN ITALIAN

physics.pop-ph↗
arXiv2013

Evaluating Astronomy Literacy of the General Public

A scientifically literate society is important for many different reasons, some of which include democratic and scientific topics. This study was performed in order to identify topics in astronomy and science in general that may not be well understood by the general public. Approximately 1,000 adults at a popular science museum in Philadelphia, PA completed True-False survey questions about basic astronomy concepts. The participants were also asked to provide their age, gender, and highest degree obtained. Although 93 +/- 0.8% of the participants correctly answered that scientists can calculate the age of the Earth, only 58 +/- 2% provided the correct response that scientists can calculate the age of the Universe. Some participants (30 +/- 1%) responded that scientists have found life on Mars. Females scored an average total score of 78 +/- 2%, whereas males scored an average 85 +/- 1%. Participants with an age of 56 and over had an average score of 78 +/- 4% compared to participants under the age of 56 that were found to have an average score of 82 +/- 2%. Lastly, participants' highest degree obtained scaled with number of correct responses, with graduate level degree earners providing the largest amount of correct responses and an average score of 86 +/- 2%.

physics.soc-ph↗
arXiv2013

Information-Based Physics and the Influence Network

This essay considers a simple model of observers that are influenced by the world around them. Consistent quantification of information about such influences results in a great deal of familiar physics. The end result is a new perspective on relativistic quantum mechanics, which includes both a way of conceiving of spacetime as well as particle "properties" that may be amenable to a unification of quantum mechanics and gravity. Rather than thinking about the universe as a computer, perhaps it is more accurate to think about it as a network of influences where the laws of physics derive from both consistent descriptions and optimal information-based inferences made by embedded observers.

quant-ph↗
arXiv2019

Is Interstellar travel to an exoplanet Possible?

It is shown that space travel, even in the most distant future, will remain confined to our own planetary system, and a similar conclusion will hold forth for any other civilization, no matter how advanced it might be, unless those extra-terrestrial species have life spans order of magnitude longer than ours. Even in such a case it is unlikely that they will travel much farther than their immediate stellar neighbourhood, as each such excursion will exhaust the resources of their home planet so much that those will dwindle rather fast and there might not be much left for the further scientific and technological advancements. So the science-fiction fancy of a "Galactic Empire" may ever remain in our fantasies only. And as for the mythical UFOs, whose quiet appearances do get reported in the press once in a while, recent explorations have shown no evidence that any such thing could have an origination within our own solar system itself. And a "quiet trip" back and forth from a distant star is almost impossible as the exhaust in any such trip will dazzle the sky like another sun or perhaps more like a gamma ray burst occurring but not in a distant part of the universe instead going off right in our own solar backyard.

physics.pop-ph↗
arXiv2013

Frictionless Racquetball?

When a ball hits a surface, does the angle of reflection always equal the angle of incidence? Not at all! Depending on the interplay of the ball's spin and speed and the force of friction, the ball's behavior after the bounce may differ dramatically. Surely some experienced racquetball, ping-pong, pool, tennis and players alike take advantage of this fact. A physics teacher, in turn, can take advantage of the fact that by observing the bounce of a ball her students can determine the coefficient of friction between the ball and the floor. All it takes is a typical video (smartphone) camera and some standard software However, this seemingly straightforward method may lead to surprises. If one wants to double check the value of the coefficient of friction by observing the second, third etc. bounces, one may find the the force of friction "does not turn on". We investigate why this happens, state a hypothesis and run some testing experiments. Teachers who would like to include an illustration of the scientific cycle at work in their classes may find this paper useful.

physics.ed-ph↗
arXiv2013

Ashes 2013 - A network theory analysis of Cricket strategies

We demonstrate in this paper the use of tools of complex network theory to describe the strategy of Australia and England in the recently concluded Ashes 2013 Test series. Using partnership data made available by cricinfo during the Ashes 2013 Test series, we generate batting partnership network (BPN) for each team, in which nodes correspond to batsmen and links represent runs scored in partnerships between batsmen. The resulting network display a visual summary of the pattern of run-scoring by each team, which helps us in identifying potential weakness in a batting order. We use different centrality scores to quantify the performance, relative importance and effect of removing a player from the team. We observe that England is an extremely well connected team, in which lower order batsmen consistently contributed significantly to the team score. Contrary to this Australia showed dependence on their top order batsmen.

physics.soc-ph↗
arXiv2013

Gravitation, Equivalence Principle, and Quantum Mechanics

Gravitation, according to General Relativity, is an attribute of space-time's geometry and hence not a force in the Newtonian sense. This is a consequence of Einstein's equivalence principle, which so far passed all experimental tests with high precision. However, the search for possible violations continues, for they, as the case may be, are expected to point towards more fundamental theoretical extensions of General Relativity. In particular, it is expected that useful insights are gained by studying the interaction between gravitational fields and genuine quantum-mechanical systems, like atoms or molecules. But this raises some fundamental issues, for General Relativity and Quantum Theory rest on partially incompatible sets of concepts. This article tries to explain in an elementary fashion how these issues recently entered modern research in atom interferometry. A shorter and editorially adapted version of this paper will appear in "Spektrum der Wissenschaft" -- the German edition of "Scientific American".

physics.pop-ph↗
arXiv2013

Development Towards Sustainability: How to judge past and proposed policies?

The scientific data about the state of our planet, presented at the 2012 (Rio+20) summit, documented that today's human family lives even less sustainably than it did in 1992. The data indicate furthermore that the environmental impacts from our current economic activities are so large, that we are approaching situations where potentially controllable regional problems can easily lead to uncontrollable global disasters. Assuming that (1) the majority of the human family, once adequately informed, wants to achieve a "sustainable way of life" and (2) that the "development towards sustainability" roadmap will be based on scientific principles, one must begin with unambiguous and quantifiable definitions of these goals. As will be demonstrated, the well known scientific method to define abstract and complex issues by their negation, satisfies these requirements. Following this new approach, it also becomes possible to decide if proposed and actual policies changes will make our way of life less unsustainable, and thus move us potentially into the direction of sustainability. Furthermore, if potentially dangerous tipping points are to be avoided, the transition roadmap must include some minimal speed requirements. Combining the negation method and the time evolution of that remaining natural capital in different domains, the transition speed for a "development towards sustainability" can be quantified at local, regional and global scales. The presented ideas allow us to measure the rate of natural capital depletion and the rate of restoration that will be required if humanity is to avoid reaching a sustainable future by a collapse transition.

physics.soc-ph↗
arXiv2013

Optimal Time-Trial Bicycle Racing with Headwinds and Tailwinds

Many time-trial and triathlon bicycle races take place on relatively flat, closed-circuit courses. In the absence of hills, riding-speed is limited almost solely by aerodynamic drag; consequently, winds can have a big effect on elapsed times. I analyze the special case of a straight out-and-back race in a steady wind, assuming the rider has a given total amount of energy to expend and can choose only two speeds - the aided speed with tailwind and the hindered speed into headwind. In this ideal circumstance the problem of choosing optimal riding speeds reduces to a constrained nonlinear optimization that can be solved with elementary calculus. My analysis reveals a practical rule of thumb that can be used more generally to choose optimal riding speeds for time-trial racing on closed-circuit courses in the presence of headwinds and tailwinds.

physics.pop-ph↗
arXiv2013

Spyhoppers and Stargazers: Can Whales See the Stars?

In Moby Dick, Herman Melville wondered how - or what - whales see with eyes on opposite sides of their heads. "It is plain that he can never see an object which is exactly ahead... Is his brain so much more comprehensive, combining and subtle than man's that he can at the same moment of time attentively examine two distinct prospects, one on one side of him, and the other in an exactly opposite direction?" he asked. It's a good question. But if Melville were alive today he might have pondered something perhaps even more intriguing: Can whales see the stars?

physics.pop-ph↗