Calculating elapsed time in different frames

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Homework Help Overview

The discussion revolves around the concept of proper time in the context of special relativity, specifically focusing on how elapsed time is calculated in different reference frames. Participants are exploring the conditions under which a frame can be considered to measure proper time between two events.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to clarify the definition of proper time and the criteria for determining which frame measures it. Questions are raised regarding the spatial separation of events and the implications for proper time measurement.

Discussion Status

The discussion is active, with participants engaging in clarifying concepts and questioning assumptions. Some guidance has been offered regarding the identification of proper frames, though there is no explicit consensus on the correctness of the reasoning presented.

Contextual Notes

There is a focus on the relationship between spatial separation of events and proper time measurement, with references to specific frames (e.g., the stick and the person) and their roles in measuring time intervals.

Abhishek11235
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Homework Statement
Consider the following problem. A stick passes with speed v though a breadthless person whose(the stick) proper length is L. How does:

Stick See the time elapsed on my clock?

I see time elapsed on my clock?

The second part is easy. In my frame ,the stick is length contracted. So the time elapsed is ## T_{my}= L/\gamma v##

Now the first part. The stick measures the time L/v for the person to pass from one end of stick to another. The stick measures proper time of L/v. Hence he should see the time elapsed on my clock to be
##T_{me}= \gamma T= \gamma L/v##

However if I calculate using Lorentz transformation, I get same answer as in a. Where is flaw in my reasoning of 2? Thanks in advance
Relevant Equations
##T= \gamma T'##
The attempt is above
 
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Does the stick measure proper time?

In general, how do you decide which frame measures the proper time interval between two events?
 
TSny said:
Does the stick measure proper time?

In general, how do you decide which frame measures the proper time interval between two events?
If the 2 events occur are measured at same position ,it is proper frame. I think I got idea. Please correct me if I am wrong. In the frame of stick,the events(when the ends come and then pass through person) are spatially separated(by length L),the stick can't constitute proper frame. It is the person who is proper frame(he measures events occurring at same position). Hence the time should be ##T_{me}=T/\gamma##. Is it right?
 
Yes. Good.
 
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