Lorentz Transformation: Finding d(gamma)/dt

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Discussion Overview

The discussion revolves around finding the time derivative of the Lorentz factor, denoted as d(gamma)/dt, within the context of special relativity. Participants explore the differentiation of the Lorentz factor with respect to time, addressing potential errors and clarifying the application of calculus principles.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant states that gamma is defined as \(\sqrt{1 - v^2/c^2}\) and provides a differentiation approach, yielding an expression for d(gamma)/dt.
  • Another participant suggests that the differentiation was performed with respect to velocity (v) rather than time (t), proposing the use of the chain rule for the correct approach.
  • A different participant points out a potential error regarding the presence of a minus sign in the differentiation process.
  • Another participant emphasizes the correct form of gamma as \(\frac{1}{\sqrt{1 - v^2/c^2}}\), implying that this should be acknowledged in the discussion.
  • Concerns are raised about the absence of the factor \(\frac{dv}{dt}\) in the differentiation equation, suggesting it is crucial for the correct formulation.
  • Reiteration of the missing factor and the minus sign is made, referencing a previous post for clarification.

Areas of Agreement / Disagreement

Participants express differing views on the correct differentiation process and the inclusion of necessary factors, indicating that the discussion remains unresolved with multiple competing interpretations.

Contextual Notes

There are indications of missing assumptions regarding the differentiation process, particularly concerning the application of the chain rule and the treatment of variables. The discussion also highlights potential errors in signs and the inclusion of terms.

PlutoniumBoy
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How do we find d(gamma)/dt?:redface:
 
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gamma is \sqrt{1- v^2/c^2}?

Differentiating that is fairly basic "Calculus I".
\gamma= \left(1- \frac{v^2}{c^2}\right)^{\frac{1}{2}}
so
\frac{d\gamma}{dt}= \frac{1}{2}\left(1- \frac{v^2}{c^2}\right)^{-\frac{1}{2}}\left(2\frac{v}{c^2}\right)

= \frac{v}{c^2\sqrt{1- \frac{v^2}{c^2}}}= \frac{v}{\sqrt{c^2- v^2}}
 
HallsOfIvy, I think you differentiated with respect to v, instead of t.
For the t derivative, use the chain rule
\frac{d\gamma}{dt} = \frac{d\gamma}{dv} \frac{dv}{dt}

And I didn't check, but you might have missed a minus sign (it's -v^2 giving -2v isn't it?)
 
Except \gamma=\frac{1}{\sqrt{1-v^2/c^2}}
which I'm sure you knew before you answered the question.
 
the factor \frac{dv}{dt}
isn't missing in the equation?

\frac{d\gamma}{dt}= \frac{1}{2}\left(1- \frac{v^2}{c^2}\right)^{-\frac{1}{2}}\left(2\frac{v}{c^2}\right)
 
facenian said:
the factor \frac{dv}{dt}
isn't missing in the equation?

\frac{d\gamma}{dt}= \frac{1}{2}\left(1- \frac{v^2}{c^2}\right)^{-\frac{1}{2}}\left(2\frac{v}{c^2}\right)
It is, along with a minus sign. See CompuChip's post.
 

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