ISSN:0002-9505    

DOI:10.1119/1.1987644

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

Salient features of the Hafele-Keating test of relativistic clock-rate changes are presented; these changes were for cesium atomic clocks which had been flown around the world, once eastward and once westward, on approximately equatorial paths. An inconsistency for an earth observer, between equal energy but different time rates for eastward and westward moving clocks, is shown to be removed if the Sagnac effect is taken into account in the synchronization of clocks in the earth reference system. Also, it is shown that an atomic clock's directional relativistic loss (gain) for an eastward (westward) circumpolar journey is velocity independent. The observed relativistic time effects may be derived as general-relativistic changes, leaving the question of special-relativistic kinetic effects on a macroscopic clock an open one empirically.

ISSN:0002-9505    

DOI:10.1119/1.1987645

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

Ideal gas models for equilibrium osmotic pressure and for nonequilibrium flow of solvent through an ideal semi-permeable membrane are presented. These models can easily be introduced in general physics courses for students of the life sciences. The models are justified in Appendices, which include a summary of the irreversible thermodynamics of flow through membranes. Some physiological examples are presented, including the Nernst equation and Gibbs-Donnan equilibrium.

ISSN:0002-9505    

DOI:10.1119/1.1987646

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

A multidisciplinary course for advanced physics and biology majors at the undergraduate level is described. The focus of the course is on the problem of how the nervous system receives, processes, and transmits information. Our main goals are to provide recognition of an important, interdisciplinary area of research, to elucidate some of what is presently known about this area, and, finally, to indicate the kinds of questions that must be asked in order to obtain an understanding of neural mechanisms.

ISSN:0002-9505    

DOI:10.1119/1.1987647

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

A new physics course devoted to phenomena of light and perception for nonscience majors is described. Content is related to student experience by reference to photography, atmospheric effects of light, Op Art, artist's techniques and palettes, optical illusions, color television, and other perception effects. The course features mixed teaching techniques within a preset schedule and includes a component of “hands-on” self-demonstrations and wide use of lecture demonstrations. Results of a professional course evaluation are presented, along with the curriculum and resource references. The success of the course is attested to by student re-enrollments in other physics courses.

ISSN:0002-9505    

DOI:10.1119/1.1987648

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

In the ordinary steam engine both the recovery of work and changes of the working substance involve the motion of a piston. Two heat engines are described here in which the gravitational field permits a separation of these two aspects. The first machine evaporates a liquid (for example, water) in the heat source, condenses it in the sink, and work is obtained from a water wheel; this machine is easy to understand, though not very efficient. The second machine is a reversible one using a Carnot cycle, again separating volume changes of the working substance from the motion of a piston. Both machines require large vertical dimensions but may someday be feasible in the exploitation of geothermal energy.

ISSN:0002-9505    

DOI:10.1119/1.1987649

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

The concepts of energy density and energy current density for a single particle in nonrelativistic quantum theory are discussed. It is shown that the energy densityεand the energy current densityQare related by the equation(δε/δt)+∇·Q = S,whereSrepresents external power sources.

ISSN:0002-9505    

DOI:10.1119/1.1987650

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

Hamilton's ancient quaternion formalism gave rise to vector analysis. Quaternions resurface once again to suggest relativistic generalizations of quantum theory and a new spin-12wave equation.

ISSN:0002-9505    

DOI:10.1119/1.1987651

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

The problem of fitting data when both variables have uncertainties is discussed, and the insufficiency of the usual least-squares calculation which does not take into account uncertainties in both variables is demonstrated. An approximate least-squares method for fitting polynomials to data which contain uncertainties in both variables is presented. The excellent results of the approximate method are compared in three illustrative examples with the results of other methods.

ISSN:0002-9505    

DOI:10.1119/1.1987652

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP

摘要:

A simple continued fraction technique for obtaining eigenvalues of some quantum mechanical problems with minimum effort is presented. The technique is intended for presentation prior to a rigorous discussion of these same problems.

ISSN:0002-9505    

DOI:10.1119/1.1987653

出版商:American Association of Physics Teachers    

年代:1974

数据来源: AIP