ISSN:0002-9505    

DOI:10.1119/1.9944

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

An analog electronic simulator for the motion of an object projected horizontally in a vertical acceleration field is described. The device features include adjustable values for both the horizontal speed and the strength of ’’gravity.’’ A metronome circuit gives aural and graphic time information. The trajectories are displayed on a storage oscilloscope. Photographs of typical families of curves are shown. [The apparatus described in this article was first prize winner in the College Demonstration category of the 1975 AAPT Apparatus Competition—Editor]

ISSN:0002-9505    

DOI:10.1119/1.9945

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

This article describes in general terms a hall demonstration of optical activity using Karo syrup. This particular demonstration is used as an eye‐catcher to lure students into stopping and also looking at the other demonstrations. [The apparatus described in this article was second prize winner in the College Demonstration category of the 1975 AAPT Apparatus Competition—Editor]

ISSN:0002-9505    

DOI:10.1119/1.9946

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

A flexible coupled‐cavity interferometer for student use has been constructed. A helium–neon laser serves as a source of radiation and as a phase‐sensitive detector of optical path changes. A phonograph turntable allows the convenient magnetic mounting of various reflecting components at varying linear velocities. Methods of calibration and possible laboratory measurements of transient events are discussed. [The apparatus described in this article was first prize winner in the College Intructional Laboratory category of the 1975 AAPT Apparatus Competition—Editor]

ISSN:0002-9505    

DOI:10.1119/1.9947

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

Field mills have been used for years to measure atmospheric electric fields. Inexpensive operational amplifiers have made possible an inexpensive and simple version of this device that is suitable for use in the classroom and instructional laboratory. The field mill allows new and exciting electrostatics experiments to be performed, in addition to breathing new life into many standard ones. [The apparatus described in this article was second prize winner in the College Instructional Laboratory category of the 1975 AAPT Apparatus Competition—Editor]

ISSN:0002-9505    

DOI:10.1119/1.9948

出版商:American Association of Physics Teachers    

年代:1975

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, Lake Forest College, Lake Forest, IL 60045.Reprints: When ordering, request Resource Letter MA‐1. Enclose 75 cents per copy (not in stamps) together with a stamped and self‐addressed envelope and send to: Executive Office, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, NY 11794.

ISSN:0002-9505    

DOI:10.1119/1.10018

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

Holography is not only a new branch of modern optics; it is also a new art form. The beginning holographer, whether he is an artist, an engineer, or a scientist, usually has difficulty in finding an easily understandable article describing the ’’how to do it’’ aspects of making a hologram. This article is intended to alleviate some of the difficulties by presenting both an understandable geometric model of the hologram and a step‐by‐step guide to the procedures involved in making a hologram.Editor’s note: Reviewers of this article have found it technically correct but question whether a presentation that treats a subject ’’from the beginning’’ is suitable in level for the American Journal of Physics. We feel that an occasional clearly written ’’how to do it’’ article that enables the nonspecialist to set up the simplest demonstrations in a field are entirely suitable for the Journal, provided an overall balance in level and subject is maintained in the Journal as a whole.

ISSN:0002-9505    

DOI:10.1119/1.10019

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

The nature of the forces causing the erratic motion of a knuckleball has been investigated by measuring the lateral force on a baseball in a wind tunnel. We have identified two possible sources of a lateral force imbalance that can give rise to the observed erratic changes in the direction of a knuckleball as it moves through the air. One of these results because the nonsymmetrical location of the roughness elements (strings) gives rise to a nonsymmetrical lift (lateral) force. A very slowly spinning knuckleball will have imposed upon it a lateral force that changes as the positions of the strings change. A knuckleball whose spin is identically zero has a constant lateral force unless a portion of the strings is precisely at a location where boundary layer separation occurs. If this happens, the point of boundary layer separation switches alternatively from the front to the rear of the strings, shifting the wake from one position to another, and thereby giving rise to a second possible alternating force imbalance. A two‐dimensional analysis of the trajectory of the baseball indicates that the measured force can cause a deflection of the baseball’s trajectory of more than a foot. An effective knuckleball should be thrown so that it rotates substantially less than once on its path to home plate.

ISSN:0002-9505    

DOI:10.1119/1.10020

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

Simple examples of elastic scattering, typically from square wells, serve as important pedagogical tools in discussion of the concepts and processes involved in elastic scattering events. An analytic solution of a model inelastic scattering system is presented here to serve in this role for inelastic events. The model and its solution are simple enough to be of pedagogical utility, but also retain enough of the important physical features to include most of the special characteristics of inelastic systems. The specific model chosen is the collision of an atom with a harmonic oscillator, interacting via a repulsive square well potential. Pedagogically important features of inelastic scattering, including its multistate character, convergence behavior, and dependence on an ’’inelastic potential’’ are emphasized as the solution is determined. Results are presented for various energies and strengths of inelastic scattering, which show that the model is capable of providing an elementary representation of vibrationally inelastic scattering.

ISSN:0002-9505    

DOI:10.1119/1.10021

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP

摘要:

It is demonstrated that the theories of optical activity given by Born and Post are exactly equivalent, in spite of their totally different physical basis.

ISSN:0002-9505    

DOI:10.1119/1.10022

出版商:American Association of Physics Teachers    

年代:1975

数据来源: AIP