Mass-Energy Conservation: E/m=c^2

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Discussion Overview

The discussion revolves around the equation E=mc^2 and its implications for the relationship between energy and mass, particularly focusing on the rearranged form E/m=c^2. Participants explore whether this ratio holds for all particles in the universe and the applicability of the complete energy-momentum relation for different types of particles, including photons.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that the rearranged equation E/m=c^2 implies a universal ratio of energy to mass for all particles.
  • Another participant agrees with the initial claim, indicating correctness.
  • A different participant introduces the complete equation E^2/c^2 - p^2 = m^2 c^2, noting that the relationship holds only for particles at rest (p=0).
  • A question is raised about whether photons satisfy the complete equation, given their momentum and lack of mass.
  • Another participant confirms that photons do satisfy the full equation.

Areas of Agreement / Disagreement

There is some agreement on the correctness of the initial claim regarding E/m=c^2, but the applicability of this relationship to all particles is contested, particularly in relation to photons and the complete energy-momentum equation.

Contextual Notes

The discussion does not resolve the implications of the energy-momentum relation for particles with mass versus massless particles like photons, leaving open questions about the conditions under which the initial claim holds.

Who May Find This Useful

This discussion may be of interest to those studying theoretical physics, particularly in the areas of relativity and particle physics.

john951007
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We know the equation E=mc^2 which correlates energy to mass.
If we rearrange the equation:
E/m = c^2 , it turns into the ratio of energy to mass is the square of the speed of light, does it mean for every particle in the universe, the ratio between the energy of the particle and its mass is the square of the speed of light?
 
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correct
 
The complete equation is ##E^2/c^2-p^2=m^2 c^2##. So the relationship you wrote holds as long as p=0, in other words for a particle at rest.
 
Does photon satisfy the full equation, because photon has momentum but does not have mass?
 
yep, the photon does satisfy the full equation.
 

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