摘要:

A version of the central limit theorem is presented that allows the study of the rate of convergence to the normal probability density of the average of independent identically distributed random variables. Particular emphasis is put on the effect due to the asymmetry of the probability density of the variables. An example is worked out that gives a convincing visual display of the theorem and its convergence.

ISSN:0002-9505    

DOI:10.1119/1.16321

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

Usually in classical dynamics the fundamental quantities of electromagnetism are considered to be the electric and magnetic fields. However, in quantum dynamics, the fundamental quantities of electromagnetism are the potentials. To solve this confusion there is a discussion of how the concepts of the central force and the conservative force in Newtonian dynamics are extended if the Galilean transformation is replaced by the Lorentz transformation. As a result, if only the conservativeness, linearity, and wave nature of field are assumed, a relativistic potential can be axiomatically defined and the dynamical equations that are similar to the equation of motion, the Lorentz condition, and the field equation for the potentials of electromagnetism can be composed. Then, the concept of charge can be introduced leading to electromagnetism without the electric and magnetic fields and the inverse‐square law. Thus even in classical dynamics the fundamental quantities of electromagnetism are the potentials. The discussion above is important in the understanding of the mutual relations among Newtonian dynamics, the special theory of relativity, and electromagnetism.

ISSN:0002-9505    

DOI:10.1119/1.16322

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

It is shown that the surface charge density on a spherical conductor (spherical in thelabframe) is uniform, regardless of its velocity.

ISSN:0002-9505    

DOI:10.1119/1.16323

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

An intermediate‐level experiment examines Fraunhofer diffraction and its implications for the image formation of a coherently illuminated object. A commercially available software package is used to provide an environment that allows interactive data acquisition and subsequent numerical and graphical analysis.

ISSN:0002-9505    

DOI:10.1119/1.16324

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

With the assumption thatncomplete single‐particle measurements αiuniquely determine then‐identical‐particle state ‖α1,α2,...,αn〉, the wavefunction ψ(α1,α2,...,αn) =〈α1,α2,...,αn‖ψ〉 is shown to be either symmetric or antisymmetric under any permutation of its arguments.

ISSN:0002-9505    

DOI:10.1119/1.16325

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

An inexpensive and easily constructed spring‐loaded dumbbell that illustrates both angular momentum conservation and mechanical instability is described.

ISSN:0002-9505    

DOI:10.1119/1.16326

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

The construction of a set of wind chimes tuned to specific pitches is described. A method for the determination of Young’s modulus based on the measured frequencies of vibration of the sample is employed in the construction of the chimes. Some complications dealing with the perception of musical pitch are also discussed.

ISSN:0002-9505    

DOI:10.1119/1.16327

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

摘要:

By using the constitutive equation for the stress tensor that yields a viscosity formula similar to the Eyring formula for non‐Newtonian fluids and solving the hydrodynamic equation for a tube flow of such fluids, a generalization is obtained of the Hagen–Poiseuille formula for velocity profile in tube flow under pressure. The volume flow rate is calculated with the velocity profile, and a method of measuring zero shear rate viscosity is suggested. As the pressure difference increases, the calculated velocity profiles become increasingly flatter in the midportion of the tube than that predicted by the Hagen–Poiseuille formula, which remains parabolic for all values of the pressure difference.

ISSN:0002-9505    

DOI:10.1119/1.16328

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.16330

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.16331

出版商:American Association of Physics Teachers    

年代:1990

数据来源: AIP