ISSN:0002-9505    

DOI:10.1119/1.18709

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18710

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18712

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18704

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

Pellegrini and Swift have recently suggested that the use of special relativity in the calculation of the electric dipole moment of a moving magnetic dipole cannot be applied to the classic experiment of Wilson and Wilson, which used rotational motion. This paper contests that view. The disagreement arises in the choice of coordinates used to represent physical quantities measured in the rotating frame. The arguments of this paper are based on Einstein’s discussion of the validity of arbitrary coordinates and the difficulty in their interpretation. Because of the lack of synchronization of clocks, caution must be used in assigning values to physical quantities in the usual coordinates that describe a rotating frame. This paper gives the detailed transformations to an inertial rest frame, where the interpretation of measurements is assured. Other aspects of the rotating frame are also discussed.

ISSN:0002-9505    

DOI:10.1119/1.18696

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

This paper reviews the relationships, both personal and professional, between J. J. Thomson and Arthur Schuster, the first physicist to attempt quantitative measurements on cathode rays in the years 1884–1890. Their relationships were unusually close, since they both attended the same college (Owens in Manchester), worked in the same research field (discharge of electricity through gases), and served many terms together in executive positions in the Royal Society of London. There were occasional misunderstandings and priority disputes between them about cathode rays, but after Thomson received his Nobel Prize in 1906 harmony again prevailed. In 1897, Thomson had available the important experimental results of Hertz, Lenard, Perrin, Wiechert, and Kaufmann on cathode rays, whereas in 1890, Schuster could benefit from none of this work. But the main reason that Thomson, and not Schuster, “discovered the electron” was that he was a better experimental physicist than Schuster.

ISSN:0002-9505    

DOI:10.1119/1.18697

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

We describe the properties of a quantum system prepared in superpositions of classically distinguishable states. These states, often called Schrödinger cat states, are of great interest at present. We discuss how they may be realized in quantum optics using nonlinear interactions and cavity quantum electrodynamics. We first describe the quantum properties of field states in a cavity, and demonstrate the interference properties which characterize superposition states and discuss how fragile they are in dissipative environments. Finally, we review current experimental approaches which may realize these states.

ISSN:0002-9505    

DOI:10.1119/1.18698

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

A teaching strategy is presented that investigates the specific heats of a simple harmonic oscillator, of a two-state system, and of ann-state system that interpolates between the two. One stage of the investigation provides a relation between the specific heats of two systems that differ by the addition of a single energy eigenstate. The strategy begins with a traditional analytic problem set whose results are investigated qualitatively in an oral exam. The oral exam raises questions that are then resolved in a second analytic problem set. As such, the strategy shows how conceptual understanding and rigorous analytic methods work together to solve problems. Although developed for a senior-level statistical mechanics course, the strategy is generally applicable to a wide range of course levels.

ISSN:0002-9505    

DOI:10.1119/1.18699

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

We give a variation of the twin paradox of special relativity in which the relationship of acceleration of the rocket twin and time dilation is clarified.

ISSN:0002-9505    

DOI:10.1119/1.18700

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP

摘要:

A simple, one-dimensional, rigid-body model of a tennis racket interacting with a tennis ball agrees well with data taken when balls are fired at a stationary, free racket. The results are then transformed into the tennis court frame of reference, where the racket is moving. Data obtained on the rotational aspects of a tennis swing are then included in the model. For ground strokes, the results are used to predict strategies that will reduce unforced errors by players. The serve is then analyzed with respect to the current problem of the speed of the game. This paper is the third of a series of papers on tennis by this author. The two previous papers were “Physics of the Tennis Racket” [Am. J. Phys.47, 482 (1979)] and “Physics of the Tennis Racket. II. The Sweet Spot” [Am. J. Phys.49, 816 (1981)].

ISSN:0002-9505    

DOI:10.1119/1.18701

出版商:American Association of Physics Teachers    

年代:1997

数据来源: AIP