Why relativistic momentum equals the following?

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SUMMARY

The discussion centers on the derivation of relativistic momentum, specifically how to express momentum (P) in terms of Lorentz factor (γ) and mass (m). The formula P = √(γ² - 1) * mc is established from the relationship between energy and momentum. The participants confirm that using the energy-momentum relation E² - p²c² = m²c⁴ simplifies the calculation of momentum compared to manipulating the velocity equations directly.

PREREQUISITES
  • Understanding of relativistic mechanics
  • Familiarity with Lorentz transformations
  • Knowledge of the energy-momentum relation
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the derivation of the energy-momentum relation E² - p²c² = m²c⁴
  • Learn about Lorentz factor (γ) and its implications in relativistic physics
  • Explore examples of momentum calculations in relativistic contexts
  • Investigate the differences between classical and relativistic momentum
USEFUL FOR

Students of physics, educators teaching relativistic mechanics, and anyone interested in advanced concepts of momentum in high-energy physics.

Foruer
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In a solution to a problem we were given, it is written that a positron momentum with energy of 2mc2
(where γ=2) is √(γ2-1)*mc = √(4-1)*mc = √3*mc

How did they get that P=√(γ2-1)*mc?
 
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You are familiar with p = ϒmv right?
And also with ϒ = 1/√(1-(v/c)2) right?

Eliminate v from the two equations and what do you get?
 
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What I get is the answer ?:) thank you :wink:
 
While it gives you the right answer, it is much simpler to use the energy-momentum relation ##E^2 - p^2 c^2 = m^2 c^4## and just solve for ##p##.
 
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