How is mass density affected by speeds near c?

  • Context: Graduate 
  • Thread starter Thread starter elliottmarter
  • Start date Start date
  • Tags Tags
    Density Mass
Click For Summary

Discussion Overview

The discussion revolves around the relationship between mass density at rest and mass density at relativistic speeds approaching the speed of light, specifically in the context of the equation M = γM₀. Participants explore the implications of relativistic effects on mass density.

Discussion Character

  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant asks about the relationship between mass density at "zero" speed and at speeds nearing the speed of light, suggesting the form M = γM₀.
  • Another participant confirms the equation M = γM₀ as a potential answer but questions whether γ should be squared or cubed, indicating uncertainty about the proportionality.
  • A different participant proposes that if "mass density" refers to "relativistic mass / volume," then γ is squared, suggesting that a moving object with γ = 2 would have half the volume but double the relativistic mass, resulting in four times the "mass density."

Areas of Agreement / Disagreement

Participants express uncertainty regarding the correct form of the relationship, particularly whether γ should be squared or cubed, indicating that the discussion remains unresolved.

Contextual Notes

Participants do not clarify the definitions of "mass density" or "relativistic mass," which may affect the interpretation of the discussion. There is also ambiguity regarding the mathematical steps involved in deriving the relationship.

Who May Find This Useful

Individuals interested in the effects of relativistic speeds on mass and density, particularly in theoretical physics and mathematical modeling.

elliottmarter
Messages
13
Reaction score
0
basically what is the relationship between mass density at "zero" speed and mass density at speeds nearing the speed of light (0.98c,0.99c etc)

in the form M = \gamma Mo if possible

Thanks a lot guys!
 
Physics news on Phys.org
sorry just saw that this should have gone in the H/W section :rolleyes:
 
elliottmarter said:
M = \gamma Mo
Isn't that the answer to your own question?
 
well, i mean i took a guess that it takes that form, but is gamma squared or cubed?...anything that could change the proportionality...you know :)

cheers
 
elliottmarter said:
well, i mean i took a guess that it takes that form, but is gamma squared or cubed?...anything that could change the proportionality...you know :)
If by "mass density" you mean "relativistic mass / volume" then yes, gamma is squared:

gamma = 2 means that a moving object has half the volume, but also double relativistic mass, so 4 time more "mass density".
 
ah i see!

thanks a lot, i think i will be frequenting these forums often in the future
 

Similar threads

High School Speed of light and this Accelerating Rocket scenario
  • · Replies 45 ·
2
Replies
45
Views
5K
Graduate Speed of Light for Bonnor Beam
  • · Replies 26 ·
Replies
26
Views
2K
Undergrad What Happens When a Planet Nears the Speed of Light Near a Black Hole?
  • · Replies 64 ·
3
Replies
64
Views
6K
Undergrad Reconciling Lorentz Four-Force Density w/ Spacelike Four-Current (##c = 1##)
  • · Replies 10 ·
Replies
10
Views
3K
High School Calculating Time taken to reach speed with Time Dilation
  • · Replies 18 ·
Replies
18
Views
2K
Undergrad How certain are we about black hole mass density?
  • · Replies 55 ·
2
Replies
55
Views
5K
High School Mechanics behind curved time causing gravitation/geodesics
  • · Replies 27 ·
Replies
27
Views
7K
High School Experimental evidence for effective mass increasing with speed
  • · Replies 11 ·
Replies
11
Views
3K
High School Theories about light and time near a black hole
  • · Replies 20 ·
Replies
20
Views
2K
Graduate Massive Object Paradox: Traveling Near Speed of Light?
  • · Replies 1 ·
Replies
1
Views
1K