Smartphone and teamwork as a methodological tool for teaching and learning physics

This research is based on the usefulness of mobile phones as a tool for students to learn about uniform rectilinear motion in vertical free fall, based on experimental practice. To evaluate whether these mobile devices allow better learning on the subject, a pre-test/post-test design was carried out with 43 students participating in the 9th grade in natural sciences. McNemar and Stuart-Maxwell non-parametric tests were applied. The proposal on the experimental practice gave satisfactory results when comparing the pre-test and post-test, in the analysis of the particular and global form of the answers.

Rebounding Cores to Build Star Cluster Multiple Populations

We present a novel approach to the riddle of star cluster multiple populations. Stars form from molecular cores. But not all cores form stars. Following their initial compression, such “failed” cores re-expand, rather than collapsing. We propose that their formation and subsequent dispersal regulate the gas density of cluster-forming clumps and, therefore, their core and star formation rates. Clumps for which failed cores are the dominant core type experience star formation histories with peaks and troughs (i.e., discrete star formation episodes). In contrast, too few failed cores results in smoothly decreasing star formation rates. We identify three main parameters shaping the star formation history of a clump: the star and core formation efficiencies per free-fall time, and the timescale on which failed cores return to the clump gas. The clump mass acts as a scaling factor. We use our model to constrain the density and mass of the Orion Nebula Cluster progenitor clump, and to caution that the star formation histories of starburst clusters may contain close-by peaks concealed by stellar age uncertainties. Our model generates a great variety of star formation histories. Intriguingly, the chromosome maps and O–Na anticorrelations of old globular clusters also present diverse morphologies. This prompts us to discuss our model in the context of globular cluster multiple stellar populations. More massive globular clusters exhibit stronger multiple stellar population patterns, which our model can explain if the formation of the polluting stars requires a given stellar mass threshold.

Sequel outcome of automobile sector on account of covid – 19 through technical analysis

The COVID – 19 pandemic has deteriorated multiple facets of the stable functioning of economies of most countries. Social restrictions associated with the immediate response to the pandemic has curtailed dynamic functioning of many industries that buttress the economic development of countries. Performance of automotive industries was expected to nosedive following the travel restrictions. One of the major sources of profit for the automotive industries in India is their consumer base in countries like U. K, Germany, and China etc. Severity of the pandemic in these countries entailed trade regulations that propelled a negative trend in the market growth of Indian automotive industries. But the economy of automotive sector of India was saved from a free fall by the countering effect of the domestic demand in private transportation. This paper presents the technical analysis on the Maruti Suzuki Private Limited to measure the stock movement of the Automobile sector in the Indian Stock Market.

“Queda Livre”: Conceitos de Cidadania em Episódio da Série Black Mirror

As inovações tecnológicas otimizaram novas possibilidades de interações pessoais no ambiente virtual, causando, no entanto, significativas mudanças comportamentais em certas ocasiões. O objetivo deste artigo é identificar as correlações das novas tecnologias com a realidade contemporânea, tendo o episódio intitulado “Nosedive” (em portuguêsbrasileiro,“Queda Livre”) da terceira temporada da série “Black Mirror” (Brooker, 2016) como contexto representativo de uma sociedade cada vez mais conectada em ambientes virtuais, exibindo comportamentos que por vezes geram dissonâncias cognitivas nos conceitos de cidadania. Após a análise com metodologia dialética, aproximando o episódio em análise com o que a sociedade tecnológica está exibindo, a conclusão é que o episódio “Queda Livre” está potencializando a cultura do impressionar, que retrata o desespero de indivíduos por serem notados e aceitos em uma sociedade, incluindo a síndrome de FOMO (Fear of Missing Out/medo de ficar de fora), patologia cada vez mais presente, que questiona conceitos de cidadania em redes sociais e ambientes virtuais. O referencial teórico para a análise inclui conceitos de Zygmunt Bauman, Massimo Di Felice, Pierre Lévy, Andrew Keen e SherryTurkle.“Nosedive”: Citizenship Concepts in Episode of the Series Black MirrorAbstractThe technological innovations have optimized new possibilities for personal interactions in the virtual environment, causing, however, significant behavioral changes on occasion. The aim of this article is to identify the correlations of new technologies with contemporary reality, with the episode entitled “Nosedive” (in Brazilian-Portuguese, “Free Fall”) from the third season of the series “Black Mirror” (Brooker, 2016) as context representative of a society increasingly connected in virtual environments, exhibiting behaviors that sometimes generate cognitive dissonance in the concepts of citizenship. After analyzing with dialectical methodology, bringing the episode under analysis closer to what the technological society is exhibiting, the conclusion is that the episode "Free Fall" is enhancing the culture of impressing, which portrays the despair of individuals for being noticed and accepted in a society, including the syndrome of FOMO (Fear of Missing Out/fear of being left out), an increasingly present pathology that questions concepts of citizenship in social networks and virtual environments. The theoretical framework for the analysis includes concepts by Zygmunt Bauman, Massimo Di Felice, Pierre Lévy, Andrew Keen and SherryTurkle.Keywords: Behavior; communication; social nets; virtual scenery; citizenship.

Dynamical Symmetries of the 2D Newtonian Free Fall Problem Revisited

Among the few exactly solvable problems in theoretical physics, the 2D (two-dimensional) Newtonian free fall problem in Euclidean space is perhaps the least known as compared to the harmonic oscillator or the Kepler–Coulomb problems. The aim of this article is to revisit this problem at the classical level as well as the quantum level, with a focus on its dynamical symmetries. We show how these dynamical symmetries arise as a special limit of the dynamical symmetries of the Kepler–Coulomb problem, and how a connection to the quartic anharmonic oscillator problem, a long-standing unsolved problem in quantum mechanics, can be established. To this end, we construct the Hilbert space of states with free boundary conditions as a space of square integrable functions that have a special functional integral representation. In this functional space, the free fall dynamical symmetry algebra is shown to be isomorphic to the so-called Klink’s algebra of the quantum quartic anharmonic oscillator problem. Furthermore, this connection entails a remarkable integral identity for the quantum quartic anharmonic oscillator eigenfunctions, which implies that these eigenfunctions are in fact zonal functions of an underlying symmetry group representation. Thus, an appropriate representation theory for the 2D Newtonian free fall quantum symmetry group may potentially open the way to exactly solving the difficult quantization problem of the quartic anharmonic oscillator. Finally, the initial value problem of the acoustic Klein–Gordon equation for wave propagation in a sound duct with a varying circular section is solved as an illustration of the techniques developed here.

Effects of shear-thickening polymer on force attenuation capacities in hip protectors

Many elderly people use hip protectors to prevent hip fractures from sideways falls. These hip protectors absorb or shunt away the energy applied to the greater trochanter. Herein, shear-thickening polymer (STP)-based hip protectors composed of STP and polyurethane foam are studied. The purpose of this study was to identify the main factor that reduces the impact force directly applied to the femoral neck region and to determine the optimal thickness of STP in hip protectors. Seven hip protectors of different thicknesses were prepared, and two sets of free-fall mechanical tests with a low impact energy of 25.1 J and moderate impact energy of 44.1 J were conducted for each hip protector. When the thickness of STP exceeded 8 mm, the resultant peak force tended to plateau under both impact conditions, and the force attenuation capacity decreased even under low impact energy conditions. Thus, a hip protector with a 6 mm or 8 mm STP and 5 mm foam was recommended. The STP was the key factor affecting force attenuation capacity, not the polyurethane foam. However, the foam also played an important role in helping the STP function and improving compliance for users.

Simple Method for Apples’ Bruise Area Prediction

From the producers’ point of view, there is no universal and quick method to predict bruise area when dropping an apple from a certain height onto a certain type of substrate. In this study the authors presented a very simple method to estimate bruise volume based on drop height and substrate material. Three varieties of apples were selected for the study: Idared, Golden Delicious, and Jonagold. Their weight, turgor, moisture, and sugar content were measured to determine morphological differences. In the next step, fruit bruise volumes were determined after a free fall test from a height of 10 to 150 mm in 10 mm increments. Based on the results of the research, linear regression models were performed to predict bruise volume on the basis of the drop height and type of substrate on which the fruit was dropped. Wood and concrete represented the stiffest substrates and it was expected that wood would respond more subtly during the free fall test. Meanwhile, wood appeared to react almost identically to concrete. Corrugated cardboard minimized bruising at the lowest discharge heights, but as the drop height increased, the cardboard degraded and the apple bruising level reached the results as for wood and concrete. Contrary to cardboard, the foam protected apples from bruising up to a drop height of 50 mm and absorbed kinetic energy up to the highest drop heights. Idared proved to be the most resistant to damage, while Golden Delicious was medium and Jonagold was least resistant to damage. Numerical models are a practical tool to quickly estimate bruise volume with an accuracy of about 75% for collective models (including all cultivars dropped on each of the given substrate) and 93% for separate models (including single cultivar dropped on each of the given substrate).

Matter-wave optics: Observing an ultracold atomic cloud expanding in free fall

This Highlight showcases the Research Paper entitled Collective-Mode Enhanced Matter-Wave Optics (Phys. Rev. Lett. 127, 100401 (2021), DOI: 10.1103/Phys- RevLett.127.100401).

Williama Goldinga Siłą bezwładu w perspektywie ontologii zorientowanej na przedmiot

The paper applies selected devices of the methodology of Object-Oriented Ontology to study William Golding’s novel Free Fall. Particular attention is given to Graham Harman’s project, whose definition of an object accounts for all beings, humans included. Within the ontological structure of an object two components can be distinguished: the “sensual object”, which can engage in relationships with other objects, and the “real object”, which refrains from any connections. The author aims to show how the main protagonist of Golding’s novel is impacted on by material objects, how other humans are perceived by him as inherently dual beings, but most importantly how the protagonist himself discovers the thing-like quality of his own human condition.