Measuring a Rod in a Running Train: Why?

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Discussion Overview

The discussion revolves around the effects of measuring the length of a rod in a moving train, particularly focusing on scenarios involving relativistic speeds versus everyday conditions. Participants explore the implications of motion on measurements and the concept of length contraction.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant inquires about the effects on the length of a rod when measured in a running train.
  • Another participant suggests that for practical measurements, the length of the rod would not change significantly unless considering extreme precision, noting that it would be shorter at very high precision levels.
  • A follow-up question addresses the scenario of a train moving at 70% the speed of light, seeking clarification on the effects in that context.
  • A later reply indicates that both the rod and the measuring stick would experience length contraction, but this would not be noticeable since both would shrink equally.

Areas of Agreement / Disagreement

Participants express differing views on the significance of length contraction, particularly in everyday versus relativistic contexts. There is no consensus on the implications of measuring lengths at relativistic speeds.

Contextual Notes

The discussion does not resolve the assumptions regarding the precision of measurements or the conditions under which length contraction becomes significant.

vinayjain
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Can anyone tell me what will happen to a length og a rod if it is measured in a running train and why?
 
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For all practical purposes, nothing will happen. Down around the 15th decimal place or so, WAY below our ability to measure it, the rod will be shorter than if the train were not moving. This is assuming that you are talking about a real train, on earth, not a thought experiment with the train moving at a relativistic speed.
 
yup...I am talking about a real train and thanx.....but can u please tell me if not a realistic train say if train is moving at the 70% speed of light then what will happen
 
Well, both the rod and your measuring stick will shrink a bit but you won't notice it since they BOTH shrink.
 

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