What Makes a Proton's Velocity Relativistic?

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Homework Help Overview

The discussion revolves around the concept of relativistic velocities in the context of calculating the de Broglie wavelength of a proton at different speeds. The original poster seeks clarification on what defines a velocity as relativistic, particularly comparing two specific speeds of a proton.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to understand the threshold at which a proton's velocity becomes relativistic, referencing two specific speeds. Some participants provide insights into the relationship between speed and the speed of light, while others question the existence of a specific percentage that defines relativistic speeds.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of what constitutes a relativistic velocity. Some guidance has been offered regarding the significance of speed as a fraction of the speed of light, but no consensus has been reached on a specific threshold.

Contextual Notes

There is a mention of the factor gamma and its relevance to relativistic calculations, indicating that the discussion may involve deeper mathematical reasoning related to relativistic effects.

jimmy_neutron
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I have been instructed to calculate the de Broglie wavelength of a proton moving at 1) 2 x 10^4 m/s and 2) 2 x 10^7 m/s

For the first velocity, the particle is not relativistic, but for the second velocity the particle is.

can someone explain to me what makes velocity 2 relativistic?
thanks.
 
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Its a significant fraction of the speed of light basically. velocity 2 is approx. 7% the speed of light while the first is 0.007%.
 
ah I see, is there a set percentage that makes a velocity relativistic?
 
To be Truthful, ANY nonzero velocity is relativistic ...
but the factor gamma (1/sqrt(1-beta^2)) is CLOSE to 1
for small beta ...
if beta = v/c = 50 %, for example, then gamma = 1.15 ...
you might be off by 15% if you calculated non-relativistically.
 

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