摘要:

An undergraduate experiment designed to study the dispersion relation and nonlinearity of surface water waves in a trough is discussed. For small amplitudes a resonance technique is used to determine the wave velocity at the frequencies of the lowest modes of the trough. For the finite amplitude case, there is subharmonic nonlinear response for the plane wave mode propagating along the trough’s length as well as waves which reflect from the trough’s sides.

ISSN:0002-9505    

DOI:10.1119/1.13776

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The usual assumption on smooth constraint reactions is shown to lead to an inconsistency for a particular problem of plane motion of a rigid body. The singular nature of the problem is illustrated by treating it as the limit of a sequence of well‐posed problems.

ISSN:0002-9505    

DOI:10.1119/1.13777

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The problem of the motions of a system in the neighborhood of one of the orbits of the same system is formulated using a variational principle. The linearized equations of motion of the deviations from the orbit are obtained from it. As an example of the use of this approach the conditions for the stability of a plane orbit are derived.

ISSN:0002-9505    

DOI:10.1119/1.13778

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The velocity of a harmonic oscillator with variable sliding friction is obtained as a function of the displacement. The ultimate stopping position is determined by an iteration procedure.

ISSN:0002-9505    

DOI:10.1119/1.13779

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The classical free‐energy density for both a monatomic and a diatomic chain of particles with harmonic coupling between nearest neighbors is calculated using (i) the transfer integral technique and (ii) real‐space renormalization. It is shown that the results agree with the classical limit of the well‐known quantum‐mechanical free‐energy densities for these chains.

ISSN:0002-9505    

DOI:10.1119/1.13780

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Transient behaviors near the oscillation threshold are investigated in a Wien bridge oscillator. Undamped relaxation oscillations familiar in masers and lasers are observed. A burst of oscillations occurs after a delay from switching on a power supply for an operational amplifier used for the oscillator. The shape of the burst closely fits to the hyperbolic‐secant function. Observed results are analyzed by van der Pol’s equation and analogies to the phenomena that appear in the magnetic resonance and laser‐type oscillators are briefly discussed.

ISSN:0002-9505    

DOI:10.1119/1.13781

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

In this essay I discuss the origin and early development of the first relativistic wave equation, known as the Klein–Gordon equation. In 1926 several physicists, among them Klein, Fock, Schrödinger, and de Broglie, announced this equation as a candidate for a relativistic generalization of the usual Schrödinger equation. In most of the early versions the Klein–Gordon equation was connected with the general theory of relativity. Klein and some other physicists attempted to express quantum mechanics within a five‐dimensional unified theory, embracing general relativity as well as electrodynamics. Although this ambitious attempt attracted some interest in 1926, its impact on the mainstream of development in quantum mechanics was virtually nil.

ISSN:0002-9505    

DOI:10.1119/1.13782

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The velocity distribution of a noble gas in a very strong magnetic field has been shown to be non‐Maxwellian. It is assumed here that a torsional suspension is immersed in such a gas. The average potential and kinetic energies of the resultant fluctuation are computed using Langevin’s method. They are found to be (kT/2), notwithstanding the reduced population of molecules at higher speeds.

ISSN:0002-9505    

DOI:10.1119/1.13783

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A unified description is given for internal space‐time symmetries for massive and massless particles. It is noted that the little groups governing the internal symmetries of massive and massless particles are locally isomorphic to the three‐dimensional rotation group orO(3) and the two‐dimensional rotation group orE(2), respectively. It is noted also that theE(2) group can be obtained from a large‐radius/flat‐surface approximation ofO(3). This procedure is then shown to be directly applicable to that of obtaining theE(2)‐like little group for massless particles from theO(3)‐like little group for massive particles in the infinite‐momentum/zero‐mass limit.

ISSN:0002-9505    

DOI:10.1119/1.13784

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

This paper is an introductory tutorial discussion of the physics of the critical magnetic field in type‐II superconductors. The emphasis is on the solid‐state physics factors affecting the magnitude of the critical field. Examples are given from current research.

ISSN:0002-9505    

DOI:10.1119/1.13785

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP