摘要:

A ball rolling without slip on a rotating platform moves along stable circular orbits with respect to the laboratory frame of reference. As the radius of the circle approaches zero, the ball remains stationary in space. If rolling friction is taken into account, an unexpected phenomenon can be observed: The spinning ball drifts toward the center of rotation and the rate at which it does so can be used to measure the coefficient of rolling friction. When atop a rotating cone, the ball moves along a circle about the axis of rotation. Due to rolling friction, balls can even move on spirals uphill.

ISSN:0002-9505    

DOI:10.1119/1.14910

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

A thought experiment is proposed in which a moving conducting shuttle encounters a gap between two conducting rails connected at one end through a bulb and a source of steady voltage. A naive application of length contraction leads to contradictory results when the encounter is examined from the rail and the shuttle frames, viz., that the bulb should switch off in one frame but should keep glowing in the other. However the interaction between the shuttle and the gap is so arranged that it is possible to analyze the experiment quantitatively in both the Lorentz frames within the framework of elementary relativistic kinematics. It is shown that the results of such a calculation lead to an exact agreement between the observed effects in the two frames. The article includes an Appendix that contains a compact bibliography of several of the paradoxes in the theory of relativity.

ISSN:0002-9505    

DOI:10.1119/1.14911

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14912

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14913

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14914

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14915

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.15325

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14917

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14918

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14919

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP