ISSN:0002-9505    

DOI:10.1119/1.19035

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18834

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18835

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

For ideal projectile motion, which starts and ends at the same height, maximum range is achieved when the firing angle is 45°. If air resistance is taken into account, the optimal angle is somewhat less than 45° and this is often considered obvious. We show here that it is not obvious by considering drag forces with different dependence on projectile speed. In some cases maximum range is achieved for launch angles greater than 45°. Simple physical arguments are given which help explain results that were found by computing trajectories and ranges.

ISSN:0002-9505    

DOI:10.1119/1.18804

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.19036

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

It is shown that certain force distributions applied to a finite portion of an infinitely long string do not produce any excitation outside the region of the applied force. The existence of such nonpropagating excitations is demonstrated by a simple example, and two general theorems concerning their nature are proven. Some analogies between nonpropagating string excitations and fields produced by nonradiating sources are noted.

ISSN:0002-9505    

DOI:10.1119/1.18829

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

In 1987, one of us (JSR) challenged the physics teaching community to examine the content of the typical introductory, calculus-based, university physics course, with an eye to meshing that content with the contemporary knowledge, level of understanding, and relative importance of the various topics in the field, and to draw upon results of the many efforts to improve that course which have been carried out over the previous 30 years. The consequence of that call to arms was the Introductory University Physics Project (IUPP). This Project, supported by the National Science Foundation over the period 1987–1995, convened several conferences during the years 1987–90 to study how to bring about the desirable changes it envisioned. The Project Steering Committee then organized the conduct and evaluation of classroom trials of four alternate course models during the academic years 1991–92 and 1992–93, at nine different colleges or universities. This report is directed to the question, “What has the IUPP accomplished?” As we shall report, the accomplishments fall into two categories. (1) As a result of the Project conferences, of frequent reports at appropriate national meetings, and reports of the course trials, many individual physics teachers have instituted small or large changes in the content and style of their courses. (2) Evaluation results from the 1991–93 trials demonstrated the importance and effectiveness of giving thematic coherence to a course structure (one of the IUPP goals), and demonstrated the feasibility of a substantial exposure to quantum physics in the introductory course. We expect textbooks based on several of the IUPP course models to be published within the next several years. In addition to studying ways to further the central goals of the Project (more contemporary physics, a less-packed list of topics, a visible theme or “story line”), study of the evaluation materials from the 1991–93 trials yielded a substantial amount of information relevant to all physics instruction at the introductory level. This information came in areas such as effective use of the introductory laboratory, strengths and pitfalls of computer use in introductory courses, and the importance of helping students most usefully allocate the time they have available for physics.

ISSN:0002-9505    

DOI:10.1119/1.18830

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

Three physical processes and the corresponding Monte Carlo algorithms are outlined, in which the numbere,the base of the natural logarithm, can be obtained. The value ofeis estimated in each case, and the three algorithms are compared.

ISSN:0002-9505    

DOI:10.1119/1.18831

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

One of the primary objectives of the introductory physics laboratory is to teach error analysis. We describe a very simple and inexpensive experiment which exposes students to the central ideas of estimation and uncertainty, and to the evaluation of theory by graphical display of data. The task is to measure the diameter of a crater formed by dropping a small steel ball into a sand-filled container, and then to deduce the functional dependence of the crater diameter on the kinetic energy of the falling ball.

ISSN:0002-9505    

DOI:10.1119/1.18832

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP

摘要:

A “real time” fast Fourier transform spectrum analyzer facilitates several experiments for an introductory course in musical acoustics. With its rapidly updated display, the time-dependent vibrations of an aluminum bar are easily studied. Using longer time acquisitions and correspondingly higher resolution facilitates the study of string inharmonicities, resonant energy transfer, and sound radiation patterns in guitar acoustics.

ISSN:0002-9505    

DOI:10.1119/1.18833

出版商:American Association of Physics Teachers    

年代:1998

数据来源: AIP