摘要:

Editor’sNote: This paper was presented as the 1978 Oppenheimer Memorial Lecture at Los Alamos Scientific Laboratories on August 17,1978.

ISSN:0002-9505    

DOI:10.1119/1.11666

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

The illustration presented in this paper can be rolled on a common cardboard tube to yield a simple demonstration of the nature of simultaneity and the propagation of light in a rotating coordinate system. The increased circumferenceC′4πrof a rotating ring can be laid off on the diagram, as can the Hafele‐Keating time offset. The device is useful at the undergraduate or graduate level.

ISSN:0002-9505    

DOI:10.1119/1.11667

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

Kepler’s first law of planetary motion is derived from Newtonian principles in a way that directly reveals the orbit as a locus of points for which the sum of distances from two fixed points is constant. The elementary differential calculus of vectors is the most advanced mathematical tool used. Also presented are derivations of the same character showing that a nonreturning comet’s orbit is either a set of points for which the difference of distances from two fixed points is constant or a locus all of whose points are equidistant from a fixed point and a fixed line. The hyperbolic orbit for inverse‐square repulsion is derived as a by product.

ISSN:0002-9505    

DOI:10.1119/1.11555

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

The topic of space industrialization and colonization affords science teachers the opportunity of having students study topics in contemporary science and technology which illustrate the role science has in shaping human destiny.

ISSN:0002-9505    

DOI:10.1119/1.11556

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

An astronomy laboratory exercise has been developed which allows students to discover for themselves the relationship between the temperature and luminosity changes in Cepheid variable stars. The equipment used is either easily constructed or readily available from among instruments commonly found in physics departments. A sinusoidally varying light source is monitored using a telescope‐photomultiplier tube combination. Filters are employed allowing color index information to be obtained. The light curves are recorded on a strip‐chart recorder, allowing each student to make his own observations and use his own chart recording in the data reductions.

ISSN:0002-9505    

DOI:10.1119/1.11557

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

A questionnaire addressed to the physics department chairmen at 92 colleges and universities with accredited engineering programs in the U. S. generated 77 responses. These responses have provided hard data concerning the physics lecture and laboratory requirements at engineering schools. Most schools offer from eight to 12 credit hours of physics, which includes one or two credit hours of laboratory work. In the last four years, there has been no significant decrease or increase in these requirements.

ISSN:0002-9505    

DOI:10.1119/1.11558

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

The case of a farmer chasing his stray goose is considered from the point of view of a physicist. It is shown that the best strategy for capturing the goose is to arrange for a head‐on encounter. The physics involved fits well in an upper level mechanics course, and helps to elucidate several important concepts.

ISSN:0002-9505    

DOI:10.1119/1.11559

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

An experiment for the intermediate undergraduate optics laboratory is described which demonstrates the effects of the polarization of light on a double‐slit Fraunhofer diffraction pattern. The experiment serves to illustrate in a single study the phenomena of diffraction, interference, coherence, some aspects of apodization, the Fresnel‐Arago law, as well as some of the interrelations between these concepts.

ISSN:0002-9505    

DOI:10.1119/1.11560

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

A simple pendulum attached to a fixed point inside a spaceship moving in a circular orbit about a planet can be in equilibrium in either 2, 3, 4, or 6 positions, of which 1, 1, 2, and 2, respectively, are stable. The number, orientation, and stability of the equilibria depend on the length of the pendulum and the location of the point of attachment relative to the center of gravity of the spacecraft.

ISSN:0002-9505    

DOI:10.1119/1.11561

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP

摘要:

The nonlinear vector product used in a previous publication to treat successive space rotations has been extended to the case of Lorentz transformations by employing an imaginary angle in place of the real angle used for the space rotation case. Expressions were derived for operations of pure Lorentz transformations and for the form of a general Lorentz transformation. The utility of the method was demonstrated by applying it to the derivations of the addition law of velocities and the Thomas precession.

ISSN:0002-9505    

DOI:10.1119/1.11562

出版商:American Association of Physics Teachers    

年代:1979

数据来源: AIP