Revista Brasileira de Ensino de Física, Volume: 23, Issue: 3, Published: 2001

• ## Relational Mechanics: Concerning a book review Artigos Gerais

Escobar, O.; Pleitez, V.

Abstract in Portuguese:

Neste artigo fazemos uma análise crítica à proposta da Mecânica Relacional tal como apresentada no livro de mesmo nome, objeto de uma resenha recente nesta revista.

Abstract in English:

We present a critical analysis of what is called Relational Mechanics, as it has been presented in a book thus entitled, which has been recently reviewed in this journal.
• ## The ballistic problem with square velocity air resistance Artigos Gerais

Ferreira, G. F. Leal

Abstract in Portuguese:

Abstract in English:

Comparing approximate solution of the ballistic problem with air resistance proportional to the square of the velocity, obtained by Johann Bernoulli in 1719, with numerical ones obtained through an analytical solution expressing the horizontal component of the velocity in terms of the angle between the tangent to the trajectory and the horizontal axis, it is found it to be sufficiently good for shooting angles so high as 20-. Results of practical interest are then calculated (football and tennis game among other cases) which may give elements to the physics teacher in this area, of knowing how good is his teaching usually ignoring air resistance.
• ## The Beer's law applied to the earth's atmosphere Artigos Gerais

Echer, E.; Souza, M. P.; Schuch, N. J.

Abstract in Portuguese:

Abstract in English:

The Beer's law has important utilizations in the atmosphere problems, when the direct solar radiation component isinvolved. In this work a summary of physical principles in atmospheric extinction of radiation and in the Beer's law derivation is presented. Also are presented some utilizations of the Beer's law in atmosphere: the calculation of the direc solar radiation ultraviolet spectrum at ground level, considering clear-sky conditions and attenuation only by Rayleigh scattering and molecular absorption. Also the Langley's method is applied to direct broadband solar radiation (0,32-0,40 mum) measured at Santa Maria, Rio Grande do Sul, in 1994, to obtain the iradiance at the top of atmosphere and the atmospheric optical depth.
• ## An Analytical Calculation of the Magnetic Field Using the Biot Savart Law

Caparelli, E.C.; Tomasi, D.

Abstract in Portuguese:

Neste trabalho apresentamos um método analítico para calcular o campo magnético em qualquer ponto do espaço, resolvendo a equação de Biot Savart no espaço recíproco. O mesmo é aplicado para expressar em termos de uma série convergente o campo magético gerado por uma distribuição de corrente circular. A comparação entre o método proposto e a integração numérica usual da lei de Biot Savart mostra uma satisfatória concordância.

Abstract in English:

This work presents an analytical method to calculate the magnetic field at any point of the space, by solving the Biot Savart equation in the reciprocal space. This is applied to express the magnetic field due to a circular current distributions as a convergent series. The comparison between the proposed method with the standard numerical integration of the Biot Savart law has shown a good agreement.
• ## An analytically solvable three-body problem Artigos Gerais

Figuerêdo, Elysandra; Castro, Antonio S. de

Abstract in Portuguese:

Analisamos um problema de três corpos interagindo mutuamente via forças harmônicas no contexto do formalismo newtoniano. Uma solução analítica exata para este problema é encontrada por meio de uma abordagem didática e os caminhos para a análise do problema de N corpos são indicados.

Abstract in English:

The problem of three particles interacting through harmonic forces is discussed within the Newtonian formalism. By means of a didactic approach, an exact analytical solution is found, and ways to extend it to the N-body case are pointed out.
• ## Internal discharge and return voltage in capacitors Artigos Gerais

Robert, Renê

Abstract in Portuguese:

Os fenômenos de descarga interna e tensão de retorno em capacitores são calculados no caso onde a resposta do dielétrico é da forma exponencial no tempo. Com esta hipótese a matemática envolvida é simples e as características gerais dos fenômenos de hereditariedade podem ser seguidas.

Abstract in English:

The phenomena of internal discharge and return voltages of capacitors are studied for the case where the dielectric response in time domain is of exponential type. The mathematics involved becomes sufficiently simple and the general feature of the heredity phenomena may be followed.
• ## The variations within main phases of the Moon time intervals Artigos Gerais

Silveira, Fernando Lang da

Abstract in Portuguese:

Os intervalos de tempo entre as sucessivas fases principais da Lua (Nova, Quarto Crescente, Cheia e Quarto Minguante) não são idênticos e apresentam pronunciadas variações ao longo do tempo. Neste trabalho é elaborada uma explicação qualitativa para essas "anomalias". É também apresentado um conjunto de equações que permite o cálculo do momento em que cada fase principal ocorre. As equações foram geradas a partir de tabelas de lunações por procedimentos de regressão não-linear; com elas é possível se estimar os momentos das fases principais com um erro padrão (desvio padrão da estimativa) de 20 min. As tabelas de lunações foram obtidas junto ao Observatório Nacional do Brasil e se referem ao período de 1940 a 2020.

Abstract in English:

The time intervals within each main phase of the Moon (new moon, first-quarter, full-moon and last-quarter) are not identical. In fact they happen to vary pronouncedly on time. A qualitative explanation for these "anomalies" is outlined at the beginnig of this text. Additionally the problem is solved using a set of equations worked out by non-linear regression procedures. The equations allow to calculate date and hour of a main phase occurence within a standard error of 20 min. The data were extracted from lunation-tables obtained at Observatório Nacional do Brasil for the period of 1940 - 2020.
• ## Comprehension of electric and magnetic field, energy and potential concepts in undergraduate students

Velazco, Sandra; Salinas, Julia

Abstract in Spanish:

Abstract in English:

Learning and teaching field, energy and potential concepts electromagnetism present special dfficulties to students and teachers. We inform on a study in domain. Comprehension of basic aspects related with those concepts attained by engineering students who had completed the course of electricity and magnetism is analysed. Results show the necessity of complementary qualitative and quantitative analysis in instruction. In traditional instruction qualitative treatments are usually delayed by treatments almost entirely centred in mathematics formalisms, whose physical mean is not clear for students.
• ## Futuros Docentes y Futuros Investigadores se Expresan sobre el Modelado en Física

Islas, Stella Maris; Pesa, Marta A.

Abstract in Spanish:

Se presenta una investigación exploratoria sobre las concepciones de modelo científico sustentadas por estudiantes universitarios de Licenciatura en Física y de Profesorado en Física. A partir de entrevistas individuales semi-estructuradas se indagaron algunas ideas clave acerca del modelado y del empleo de modelos. Los resultados muestran a los futuros licenciados con una postura frente al tema que es acorde con las consensuadas en las epistemologías actuales, y se registran evidencias de su experiencia en el manejo de modelos. Ello no ocurre con los futuros docentes, quienes presentan ms acentuadamente las dificultades que, sobre este tema, se han detectado en otras investigaciones con estudiantes.

Abstract in English:

An exploratory research on scientific model's conceptions sustained by university students of Physics and Physics Teaching is presented. Starting from individual semi-structured interviews, some key ideas were investigated about modeling and the use of models. The results show that future physicists adopt a posture in agreement with the consensual ones in the current epistemologies. Also, evidences of their experience in the handling of models are registered. Among the future teachers the situation is different. They present difficulties similar to those that have been detected in other researches with students.
• ## A Didactic System for the Physics Teaching: Learning

Arruda, José Ricardo Campelo; Marín Antuña, José

Abstract in Spanish:

Abstract in English:

The objective of this investigation is to know which will be the formative regularities of the basic logical and psychological structures of the theoretical thought in the students in the courses of the technological area, as a consequence of the teaching of the proposed didactic model, that uses the foundations of the Theory of the Activity, Theoretical Generalization and the Sistemic Structural-Functional Method for organization of the content to be developed. The accomplished investigation demonstrates that it is possible to elevate the level of development of the logical through the teaching of a Discipline, as the Physics, when it uses the Activity of Study and the structural-functional method of organization of the content. The results of the investigation point that the proposed didactic model, puts in correspondence the scientific method of obtaining of the knowledge discovered by the Physics Epistemology, with the teaching activity and the psychology of the learning of this science. The investigation showed that the traditional teaching that it prioritizes the dichotomy among the teaching of the theoretical and experimental part, doesn't favor an effective learning; therefore, it is necessary to consider the Physics process teaching-learning in systemic form and developed as a group of interlinked parts, possessing a logic interns characteristic, where the evaluation plays important paper in the feedback of the process, necessary to get the planned objectives, so much in the teacher's vision, as in the student's vision, providing a quality teaching.
• ## Notes for a History of the Brazilian Physical Society História Da Física E Áreas Afins

Salinas, Silvio R. A.

Abstract in Portuguese:

Este artigo é uma versão do meu discurso por ocasião da inauguração do edifício próprio da Sociedade Brasileira de Física (SBF) em 1998. A partir da análise dos Boletins e Atas de reuniões, procuro discutir aspectos relevantes da atuação da SBF nos últimos trinta anos. Espero que este trabalho preliminar consiga encorajar historiadores a escrever uma história completa da SBF.

Abstract in English:

This paper was addressed at the inauguration of the new headquarters of the Brazilian Physical Society (SBF) in 1998. On the basis of the Bulletins and meeting reports, I try to discuss relevant aspects of the society in the last thirty years. I hope this preliminary work may encourage historians to write a more complete history of the SBF.
• ## Discussion on the concepts of inertial mass and gravitational mass Notas E Discussões

Castellani, Otávio Cesar

Abstract in Portuguese:

Por mais de dois séculos a igualdade entre massa inercial e massa gravitacional foi um mistério na Física. Até que no início do século XX nasceu uma teoria que explicasse essa igualdade. Neste trabalho discutimos os conceitos referentes a essas massas bem como a origem da teoria da Relatividade Geral, que tem como base justamente a igualdade entre elas. O texto a seguir serve também como objeto de discussão para alunos de ensino médio e de ensino superior, pois fornece uma compreensão mais sólida dos conceitos envolvidos.

Abstract in English:

For more than two centuries, the equality between inertial mass and gravitational mass has been a mistery in Physics, until early in the XX century a theory that could explain such equality appeared. In the present work we discuss the concepts concerning those masses, as well as the origin of the theory of General Relativity, which relies in their very equality. The following text is also suitable as a discussion item for high-school and undergraduate students, providing a more solid understanding of the concepts involved.
• ## Comparative study on the contents of Quantum Mechanics and Modern Physics courses Notas E Discussões

Araújo, Weslei Silva de; Rodrigues, Clóves Gonçalves

Abstract in Portuguese:

Neste trabalho fazemos uma comparação entre o curso de Física Moderna (ministrado nos cursos de Licenciatura e Bacharelado em Física) e o de Mecânica Quântica ministrado apenas nos cursos de Bacharelado em Física. A comparação entre o conteúdo ministrado no curso de Física Moderna com o ministrado no curso de Mecânica Quântica foi feita a partir dos livros de textos mais adotados no ensino destas duas disciplinas no país. Abordamos também a importância do curso de Física Moderna para os licenciandos em Física.

Abstract in English:

In this work, we make a comparison between the course of Modern Physics (taught on the Physics Teacher Preparation and Bachelor of Physics Programs) and the Quantum Mechanics' course taught only on the Bachelor of Physics Program. The comparison between the contents taught on the Modern Physics course and the contents taught on the Quantum Mechanics' course, was based on the most used books in the teaching of both disciplines in Brazil. We also discuss the importance of the Modern Physics course to future physics teachers. in Physics.
• ## Dinâmica Estocástica e Irreversibilidade, por Tânia Tomé e Mário José de Oliveira, EDUSP, 241 p. (2001) Resenha

Mizrahi, Salomon S.
• ## Errata

Cavalcante, Marisa Almeida
Sociedade Brasileira de Física Caixa Postal 66328, 05389-970 São Paulo SP - Brazil - São Paulo - SP - Brazil
E-mail: marcio@sbfisica.org.br