Energy in a String Wave

Autor/in	Ng, Chiu-king
Titel	Energy in a String Wave
Quelle	In: Physics Teacher, 48 (2010) 1, S.46-47 (2 Seiten)Infoseite zur Zeitschrift PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0031-921X
DOI	10.1119/1.3274362
Schlagwörter	Kinetics; Physics; Motion; Geometric Concepts; Energy; College Students; Thinking Skills; Science Instruction; Science Education; Teaching Methods; Science Teachers; Foreign Countries; Hong Kong + Suchen Sie Ihr Suchwort? Kinetik; Physik; Bewegungsablauf; Elementare Geometrie; Energie; Collegestudent; Denkfähigkeit; Teaching of science; Science education; Natural sciences Lessons; Naturwissenschaftlicher Unterricht; Naturwissenschaftliche Bildung; Teaching method; Lehrmethode; Unterrichtsmethode; Science; Teacher; Teachers; Science teacher; Wissenschaft; Lehrer; Lehrerin; Lehrende; Ausland; Hongkong
Abstract	When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed "simple harmonic". They also know elements of the string at the highest and the lowest positions--the crests and the troughs--are momentarily at rest, while those at the centerline (zero displacement) have the greatest speed, as shown in Fig. 1. Irrespective of this, they are less familiar with the energy associated with the wave. They may fail to answer a question such as, "In a traveling string wave, which elements have respectively the greatest kinetic energy (KE) and the greatest potential energy (PE)?" The answer to the former is not difficult; elements at zero position have the fastest speed and hence their KE, being proportional to the square of speed, is the greatest. To the PE, what immediately comes to their mind may be the simple harmonic motion (SHM), in which the PE is the greatest and the KE is zero at the two turning points. It may thus lead them to think elements at crests or troughs have the greatest PE. Unfortunately, this association is wrong. Thinking that the crests or troughs have the greatest PE is a misconception. (As Provided).
Anmerkungen	American Association of Physics Teachers. One Physics Ellipse, College Park, MD 20740. Tel: 301-209-3300; Fax: 301-209-0845; e-mail: pubs@aapt.org; Web site: http://scitation.aip.org/tpt
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10