ISSN:0002-9505    

DOI:10.1119/1.13760

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.13762

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

We examine the roles of the equant point and the eccentric deferent circle in Ptolemy’s planetary theory. The necessity of these features of the model is demonstrated empirically by a study of the retrograde arcs of Mars. Finally, these results are used, together with available historical evidence, to suggest the line of investigation that probably led Ptolemy to his discovery of the equant.

ISSN:0002-9505    

DOI:10.1119/1.13764

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The resolutions to the paradox of Schrödinger’s cat engendered by three major perspectives on quantum mechanics—quantum logic, the many worlds interpretation, and the Copenhagen interpretation—are discussed. The core of each perspective is revealed in the process. Each resolution to Schrödinger’s cat has a counterpart which solves the logical paradox known as the unexpected hanging. The rather striking parallels serve to emphasize several points. First, the quantum paradox is an epistemological and not a physical one. Second, the three interpretations mentioned, unlike some others, are faithful to this understanding. And third, the pitfalls in these two paradoxes have a somewhat universal character.

ISSN:0002-9505    

DOI:10.1119/1.13765

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A steady‐state technique for finding the thermal resistance of rigid thermal insulation is discussed. The method, which is suitable for use in the general physics laboratory, can be understood in terms of a simple electrical analogy.

ISSN:0002-9505    

DOI:10.1119/1.13766

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The solution to a puzzle proposed by Merzbacher in this Journal [Am. J. Phys.48, 178 (1980)], the determination of the electric field outside a long straight wire carrying a constant current, is discussed.

ISSN:0002-9505    

DOI:10.1119/1.13767

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A conservative model for the damped harmonic oscillator is constructed by attaching a string of infinite extent to the oscillator’s mass. This system may be used to illustrate, in simple terms, a number of important concepts such as radiation damping, the characteristic impedance of a wave propagating medium, Brownian motion, and the Langevin equation.

ISSN:0002-9505    

DOI:10.1119/1.13768

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Experimental and computational procedures are outlined for establishing the surface tension of a sessile drop of liquid. Measurements of a drop are made from a microphotograph or by using a novel diverging laser beam projection method. The sessile drop differential equation is found from hydrostatic considerations; this is solved numerically using a Runge–Kutta scheme. A best‐fit solution to the experimental curve is found by adjusting two parameters: the drop apex radius of curvature and the surface tension. Reasonable agreement with experiment is obtained.

ISSN:0002-9505    

DOI:10.1119/1.13769

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The general properties of the pair correlation function are reviewed. The computer simulation method of molecular dynamics is used to obtain this function for a variety of conditions for a two‐dimensional Lennard–Jones model. It is shown that the pair correlation function is an excellent tool for the investigation of molecular order.

ISSN:0002-9505    

DOI:10.1119/1.13770

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A ball that rolls on parallel tracks, whose width is less than the diameter of the ball, experiences both translational and rotational motions. The linear accelerations of the ball for cases of rolling and slipping are derived theoretically, and these accelerations have also been determined by performing experiments when the width and the angular elevation of the tracks are controlled. Data show when slipping occurs for the rolling motion, and the onset of slipping is used to compute the coefficient of kinetic friction for a sphere. A second method of determining the coefficient of friction, for the sphere slipping without rolling, provides confirmation for this analysis.

ISSN:0002-9505    

DOI:10.1119/1.13771

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP