ISSN:0002-9505    

DOI:10.1119/1.13549

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

An elementary derivation is given for the shape of the wake pattern of a boat traveling at constant velocity in deep water. We find essentially the same results as those found in standard treatments, but our mathematics is easier. All results follow from the fact that the group velocity is half the phase velocity.

ISSN:0002-9505    

DOI:10.1119/1.13550

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Recent accusations of scientific fraud have raised serious questions both for science policy and science itself. If experimental results cannot be trusted then science becomes virtually impossible. Four cases from twentieth‐century physics are examined to see if the normal procedures of science provide adequate safeguards against fraud. I conclude that repetition of experiments, particularly for those of theoretical importance, does provide a sufficient safeguard.

ISSN:0002-9505    

DOI:10.1119/1.13551

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A unified approach to science teaching based upon a certain class of quantities which play fundamental roles in classical and modern physics is introduced. These quantities share the property of being substance‐like, that is, each can be pictured to be contained in bodies and to flow from one body to another like a kind of ‘‘stuff.’’ Such quantities include, for example, energy (=mass), momentum, angular momentum, electric charge, particle number (=amount of substance), and entropy. When emphasizing substance‐like quantities, the breakup of physics into sub‐branches is nothing more than a classification of natural processes according to the substance‐like quantity playing the dominant role in each case. The method of presentation, however, remains the same from one sub‐branch to another: different natural processes can be simply visualized and quantitatively described according to the same formal rules in terms of the increasing, decreasing, and flowing of the respective substance‐like quantities in each case. Thus knowledge of a single branch of physics already provides an analogy for the ways and means by which processes are described in other branches (including chemistry and biology) as well. These claims are illustrated with the help of a few simple examples.

ISSN:0002-9505    

DOI:10.1119/1.13552

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A simple circuit comprising an operational amplifier and anRCfeedback network is configured into a resonant circuit. It behaves as a simple harmonic oscillator for small input signals and changes to an anharmonic oscillator when slew limiting occurs. The circuit is analyzed and the theoretical gain is compared to experimental data for the two cases.

ISSN:0002-9505    

DOI:10.1119/1.13553

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

According to the general theorem of equipartition 〈χ∂H/∂χ〉=kT, where χ is any appropriate coordinate or component of momentum. More generally, iffis any suitable function of the coordinates and momenta 〈 f∂H/∂χ〉=kT〈∂f/∂χ〉. This relation is used to obtain by elementary means relations describing the dependence of the energy of a relativistic ideal gas upon the parameterkT/mc2.

ISSN:0002-9505    

DOI:10.1119/1.13518

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Expressions for the time‐dependent scattering wave function,S‐matrix elements, and the transition rate are derived using simple time‐dependent perturbation theory as it is presented in elementary quantum‐mechanics texts.

ISSN:0002-9505    

DOI:10.1119/1.13519

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Motion of an electron in a periodic potential is analyzed with use of a simple classical model. A calculation and a demonstration experiment described show the usefulness of the model in the teaching of solid‐state physics.

ISSN:0002-9505    

DOI:10.1119/1.13520

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

In this paper the distinction between ‘‘science’’ and ‘‘nonscience’’ is considered, and the essential ingredients which characterize scientific method such as the construction of models, hypotheses, theories, and paradigms in the physics enterprise are discussed.

ISSN:0002-9505    

DOI:10.1119/1.13521

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Using a common laboratory apparatus and a spark timer, consecutive positions of a moving object with respect to time in a rotating frame of reference can be obtained. Experimental data are analyzed by means of a simple graphic method, directly based on the vectorial definitions of mean velocity and acceleration. Thus the Coriolis acceleration vector can be directly obtained on every point of the trajectory and the relation for the Coriolis acceleration can be clearly verified.

ISSN:0002-9505    

DOI:10.1119/1.13539

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP