Relativistic contraction of an accelerated rod

The relativistic motion of an arbitrary point of an accelerated rigid rod is discussed for the case when velocity and acceleration are directed along the rod's length. The discussion includes the case of a time-dependent force applied to a single point, as well as a time-independent force arbitrary distributed along the rod. The time dependence of the rod's relativistic length depends on the application point of the force, but after the termination of acceleration the final velocity and length do not depend on it. An observer on a uniformly accelerated rod feels an inertial force which decreases in the direction of acceleration. The influence of non-rigidity of realistic rods on our results is qualitatively discussed.Comment: 11 pages, 1 figure included, revised version, accepted for publication in Am. J. Phy

Interpretation miniatures

Most physicists do not have patience for reading long and obscure interpretation arguments and disputes. Hence, to attract attention of a wider physics community, in this paper various old and new aspects of quantum interpretations are explained in a concise and simple (almost trivial) form. About the "Copenhagen" interpretation, we note that there are several different versions of it and explain how to make sense of "local non-reality" interpretation. About the many-world interpretation, we explain that it is neither local nor non-local, that it cannot explain the Born rule, that it suffers from the preferred basis problem, and that quantum suicide cannot be used to test it. About the Bohmian interpretation, we explain that it is analogous to dark matter, use it to explain that there is no big difference between non-local correlation and non-local causation, and use some condensed-matter ideas to outline how non-relativistic Bohmian theory could be a theory of everything. We also explain how different interpretations can be used to demystify the delayed choice experiment, to resolve the problem of time in quantum gravity, and to provide alternatives to quantum non-locality. Finally, we explain why is life compatible with the 2nd law.Comment: 12 pages, revised, new references, accepted for publication in Int. J. Quantum In