摘要:

The motion picture film of the Kennedy assassination taken by Abraham Zapruder was one of the most important exhibits examined by the Warren Commission. The author uses the tools of the physicist to draw some conclusions that escaped the notice of the Commission and its expert FBI photointerpreters. Among the subjects treated are (1) the timing of the gun shots, (2) a theoretical and experimental investigation of the ’’backward snap’’ of the President’s head immediately after he was killed—yielding the surprising result that it was consistent with a shot fired from the rear, (3) the speed at which the camera was running, and (4) a previously undetected deceleration of the President’s automobile just before the final shot. The emphasis throughout is not on the assassination but rather on the application of elementary physics principles to the solution of practical problems.

ISSN:0002-9505    

DOI:10.1119/1.10297

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Prepared at the request of the AAPT Editorial Board for Resource Letters. This is one of a series of Resource Letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course contents in specified fields. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one Letter on some of the main subjects of interest. Comments on these materials as well as suggestions for future topics will be welcomed. Please send such communications to Professor Aaron Owens, Editor, Resource Letter Board, Department of Physics, Kenyon College, Gambier, Ohio 43022.Notation: The letter E after an item number indicates elementary level; the letter I indicates intermediate level; and the letter A indicates advanced material. An asterisk (*) indicates those references we feel to be especially helpful.Reprints: When ordering, request Resource Letter EMAA‐2. Enclose 75 cents per copy (not in stamps) together with a stamped and self‐addressed envelope and send to Melba Phillips, Acting Executive Officer, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, New York 11794.

ISSN:0002-9505    

DOI:10.1119/1.10298

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Experience in a physical science course for preservice elementary teachers, inservice elementary teachers, and other nonscience majors has led to the identification of certain specific factors and procedures that seem to assist the attainment of the formal operational level of intellectual development on the part of students who are initially at a concrete or transitional stage.

ISSN:0002-9505    

DOI:10.1119/1.10299

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

The uncertainty principle is used to derive the ultimate spectral width of the laser beam. The resulting expression is the Schawlow–Townes formula. The derivation is simple and can readily be incorporated into an introductory course on lasers. The derivation can also be used in a modern physics course to illustrate the usefulness of the uncertainty principle.

ISSN:0002-9505    

DOI:10.1119/1.10133

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

We follow through the different variants of Einstein’s intuitive photon‐in‐a‐box derivation of the inertia of energy, and end with the very simple ’’radiating atom’’ derivation.

ISSN:0002-9505    

DOI:10.1119/1.10134

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

The identification of a string as a curve allows the statement of a physical postulate which has as an immediate consequence the differential equation of the curve. The applied force appears as the gradient of the tension. It is possible to rewrite the differential equation as an equation for a geodesic in a transformed space, with the tension now incorporated into the metric. The field equation can be chosen to be the equation relating the transformed scalar curvature to the tension. The geometrization of physics is traceable. By the same procedure, the differential equation of a light ray may be derived, and the index of refraction may be related to the distorted geometry.

ISSN:0002-9505    

DOI:10.1119/1.10135

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

A one‐to‐one correspondence is demonstrated for Doppler shifted frequencies measured in different inertial reference frames. This result is reconciled with frequency splitting encountered in the complex Doppler effect. The analysis emphasizes the concept that it is not always sufficient to describe the Doppler effect for plane waves in homogeneous, isotropic, dispersive media by using only the conventional frequency equation ω=γ (ω′+v⋅k′). These ideas are illustrated in detail for the case of the cold plasma where the extra Doppler frequencies are given specific physical interpretations.

ISSN:0002-9505    

DOI:10.1119/1.10136

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

By replacing optical position sensors with electrical contact switches and by using an integrated‐circuit timer with digital readout, the time required for a ball bearing to fall may be measured consistently to about 0.1 msec. The acceleration of gravity may then be determined to better than one part per thousand.

ISSN:0002-9505    

DOI:10.1119/1.10277

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Using explicit tetrads for any given metric and Fock–Ivanenko coefficients of the generally covariant Dirac equation, we develop a formal method to relate the wave function in a noninertial frame to that in the inertial frame. The resulting equivalence transformations are exact. The familiar cases of the rotating frame and generalized hyperbolic motion are given as examples.

ISSN:0002-9505    

DOI:10.1119/1.10256

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

The problem of teaching and evaluating decision‐making skills in physics is discussed. What is needed is a system which will teach students both (1) how to utilize the techniques of physics to solve open‐ended problems in a creative and disciplined way and (2) an understanding of the role these skills play in the ongoing process of physics. The ’’guided design’’ method of instruction is described and suggested as a solution to the first problem. An application of guided design to a multidisciplinary course is then discussed that offers a possible solution to the second problem.

ISSN:0002-9505    

DOI:10.1119/1.10360

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP