A dimensional problem in relativistic mechanics

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SUMMARY

The discussion centers on the relativistic form of Newton's second law, specifically the equation {F}=\frac {{\gamma}^3 {m} {v}^2}{{c}^2} + \gamma {m} {a}. Participants highlight a dimensional inconsistency where the first term appears to have the dimension of mass rather than force. The equation's proper interpretation requires including the term for acceleration, dv/dt, to maintain dimensional consistency. The importance of the Lorentz factor, γ, is emphasized in the context of relativistic mechanics.

PREREQUISITES
  • Understanding of relativistic mechanics and the Lorentz factor (γ)
  • Familiarity with Newton's laws of motion
  • Basic knowledge of calculus, specifically derivatives
  • Concept of force in the context of special relativity
NEXT STEPS
  • Study the derivation of the Lorentz factor (γ) in special relativity
  • Learn about the relationship between force and momentum in relativistic physics
  • Explore the implications of relativistic acceleration on mass and force
  • Review the section on force in the Wikipedia article on special relativity
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Physics students, educators, and professionals in the field of relativistic mechanics seeking to deepen their understanding of force equations in a relativistic context.

ShayanJ
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[tex]{F}=\frac {{\gamma}^3 {m} {v}^2}{{c}^2} + \gamma {m} {a}[/tex]

You all know this equation.Relativistic Newton's second law.
The problem is as follows:
As you know [tex]\gamma[/tex] is dimensionless.So the first term of the right side has dimension of mass.but it should have the dimension of force!
what's wrong here?
thanks
 
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Shyan said:
[tex]{F}=\frac {{\gamma}^3 {m} {v}^2}{{c}^2} + \gamma {m} {a}[/tex]

You all know this equation.Relativistic Newton's second law.
The problem is as follows:
As you know [tex]\gamma[/tex] is dimensionless.So the first term of the right side has dimension of mass.but it should have the dimension of force!
what's wrong here?
thanks

Hi Shyan. :smile:

F = dp/dt.

However, the equation that you write, I don't know it.
See http://en.wikipedia.org/wiki/Special_relativity (scroll down to the section on force).
It looks like you forgot a dv/dt term.

Harald
 
You left out a factor. The first term is actually

γ3 m/c2 (v.a) v
 

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