ISSN:0002-9505    

DOI:10.1119/1.14758

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14759

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14761

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

The confirmation in 1759 of Halley’s prediction for the return of the comet of 1682 was a triumphant scientific event, helping to convince a broad public that comets, like other celestial bodies, were knowable natural objects. Nevertheless, the frightening possibility that an unknown comet could appear at any time led to a startling degree of panic on a later occasion, when a study by Lalande on the statistical probability of a collision between earth and a comet was construed by rumor as a prophecy of imminent destruction.

ISSN:0002-9505    

DOI:10.1119/1.14763

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

The fundamental laws of microscopic physics are time‐reversal invariant. The laws governing the behavior of macroscopic systems are not time‐reversal invariant. If macroscopic systems are collections of microscopic components, how do we reconcile this dichotomy?

ISSN:0002-9505    

DOI:10.1119/1.14764

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

The dynamically shifted oscillator is described by an equation of motion which includes both a Hookian restoring force and a nonlinear force which depends only upon the sign of the displacement. Exact expressions are obtained for the amplitude‐dependent frequency and for the displacement waveform. The theory is applied to the study of the vibrations of the two‐point librator and of the spring doorstop.

ISSN:0002-9505    

DOI:10.1119/1.14765

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

Diamagnetism does not exist as a classical phenomenon. Yet many elementary physics texts attempt to give ‘‘insight’’ into this subject using purely classical physics. We believe that these approaches mislead rather than help the students. On the other hand, just as semiclassical methods are employed in the chapters on quantum mechanics, these methods may be used to give an acceptable ‘‘explanation’’ of diamagnetism.

ISSN:0002-9505    

DOI:10.1119/1.14766

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

Several examples are given in which the soliton solutions belonging to well‐known nonlinear differential equations arise as simple limits of the Jacobian elliptic functions. The knowledge of the solutions of a single ordinary nonlinear differential equation is sufficient for the subsequent derivation of soliton solutions. Various explicit examples are worked out.

ISSN:0002-9505    

DOI:10.1119/1.14767

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

There has been a great deal of public concern about the dangers of buried radioactive waste from the nuclear industry. The rational approach to evaluating these concerns is to develop quantitative estimates of the health impacts to be expected from these wastes, and compare them with the health impacts of wastes from alternative technologies. It is our purpose here to outline that process and develop the results.

ISSN:0002-9505    

DOI:10.1119/1.14768

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP

摘要:

The phenomenon of gravitational repulsion is described within the context of the general theory of relativity. The theory implies that if a vacuum has a nonvanishing energy, then its gravitational mass density will be negative. In particular, this implies that the universe will expand exponentially during the vacuum dominated inflationary era. It is suggested that the observed expansion of the universe may be explained as a result of repulsive gravitation.

ISSN:0002-9505    

DOI:10.1119/1.14769

出版商:American Association of Physics Teachers    

年代:1986

数据来源: AIP