Mass of fuel would ALSO increase as spaceship comes near the speed of light

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Discussion Overview

The discussion revolves around the implications of relativistic mass and energy requirements for a spaceship approaching the speed of light. Participants explore the relationship between the mass of the spaceship, the mass of the fuel, and the energy output as the spaceship accelerates. The conversation touches on concepts from special relativity, energy conservation, and the nature of mass in different frames of reference.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that as a spaceship approaches the speed of light, both the mass of the spaceship and the mass of the fuel increase, suggesting that this could lead to an exponential gain in kinetic energy.
  • Others argue that the relativistic mass increase does not equate to a real change in the quantity of fuel, asserting that from the perspective of the spaceship, the mass remains unchanged.
  • One participant emphasizes that the invariant mass of the objects does not change, and thus the energy output of a system does not increase simply due to relativistic effects observed from another frame.
  • Another viewpoint suggests that the captain of the spaceship would not notice any relativistic effects and could continue to accelerate at a constant rate without perceiving any change in mass or fuel consumption.
  • There are claims that the energy of the system increases relative to an outside observer, but the fundamental properties of the fuel and its energy output remain constant.

Areas of Agreement / Disagreement

Participants express differing views on the implications of relativistic mass and energy conservation. There is no consensus on whether the increase in relativistic mass affects the energy output of the fuel or the spaceship, leading to an ongoing debate about the interpretations of special relativity.

Contextual Notes

Limitations include the dependence on definitions of mass (relativistic vs. invariant) and the assumptions about frames of reference. The discussion does not resolve the complexities of energy conservation in relativistic contexts.

  • #61
i know you say my way will not work but i'v tried it your way and my way and they get the exact same answer. it's my presentation that is faulty. I'm not describing my method in clear detail. i'll try again. first i use m=e/c^2. then i multiply m*light speed to get Newtons. then i divide Newtons by ships mass to get velocity after firing the laser. maybe it works because you could be accelerating @ 300000000m/sec^2 for one second. it's wrong i guess i just got lucky somehow it gets the same answer. anyways thanks for the work and the nice handy dandy equation. I'm glad we have guys like you to steer us fumbling laymen in the right direction again thanks and let me get off this year ond thread. bye.
 
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  • #62
Hi jonnyk
If you look closer at the discussion of relativistic rockets at Baez's site you'll notice total energy is conserved. Read it a bit closer and you'll see what I mean.
 
  • #63
qraal said:
Hi jonnyk
If you look closer at the discussion of relativistic rockets at Baez's site you'll notice total energy is conserved. Read it a bit closer and you'll see what I mean.
Egads! I just noticed how old the post I am replying to was. Oops.
 
  • #64
mass times velocity gives momentum but that momentum and mass applied to an inert object has an effect.
 

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