Constatly accelerating spacecraft

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Discussion Overview

The discussion revolves around the theoretical implications of a spacecraft that can accelerate indefinitely at 1 gee or more, exploring the calculations related to time and velocity in the context of both Galilean and relativistic mechanics. Participants are interested in understanding how to derive equations for subjective and externally measured time, as well as the final velocity of the spacecraft.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant proposes using Galilean mechanics to calculate time and final velocity, suggesting equations T = √(2D/A) and v_final = √(2AD).
  • The same participant expresses interest in incorporating relativity into their calculations, noting the need to consider subjective time and the effects of length contraction.
  • Another participant provides a link to a resource that discusses the relevant relativistic concepts, indicating it may assist in the project.
  • A later reply references a specific book as a source for deriving the equations related to the topic.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the derivation of the equations or the application of relativity, as the discussion includes requests for clarification and additional resources.

Contextual Notes

The discussion lacks detailed derivations of the equations mentioned, and there is an implicit assumption that the acceleration remains constant throughout the journey. The implications of relativistic effects on time and velocity are not fully resolved.

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This is not a homework problem. It is personal project of mine. Pleases help

Say you have a spacecraft that for some advanced propulsion technology is able to accelerate at 1 gee or more indefinitely. This allows the crew walk around as in a gravity and, I think, permit slower than travel between the stars without the crew dying of old age.

You know the distance to your destination and you know the acceleration the crew experiences is constant.

To simplify things assume no deceleration leg. Once we figure out how to calculate that a more realistic flight should be trivial to extrapolate.

Using Galilean mechanics I would;

[tex]T = \sqrt{ \frac{2 D}{A}}[/tex]

and

[tex]v_{final} = \sqrt{2 A D}[/tex]

but I want to see how relativity comes into play. The speed in the second equation isn't real and can only be found by mixing reference frames (the non length contracted distance over subjective time).

I want to find both subjective and externally measured time as well as the real final velocity. We have non-relativistic distance and subjective acceleration.

Anyone?
 
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Good page on this very subject here:

http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html
 
Last edited by a moderator:
Ah thank you. Your link will help me complete my project. I am curious though if anyone knows how one arrives at such equations.
 
{~} said:
Ah thank you. Your link will help me complete my project. I am curious though if anyone knows how one arrives at such equations.
Well, you could start with p. 240-242 of this book for several of those equations.
 

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