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## Main Question or Discussion Point

From what i heard, my friend told me relatvistic mass has just been recently proven wrong. Is that right????

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From what i heard, my friend told me relatvistic mass has just been recently proven wrong. Is that right????

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No this is not right.misogynisticfeminist said:From what i heard, my friend told me relatvistic mass has just been recently proven wrong. Is that right????

How would one prove relativistic mass to be wrong ???

marlon

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No. Absolultely not. Where did he get that idea from??misogynisticfeminist said:

Pete

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Tempest99 is just a new user name for Physicsguru. Accordingly, I have deleted all of his posts and any posts referencing them.

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Thanks Janus for getting rid of these crappy posts

marlon

marlon

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Tom Mattson

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You can't prove it wrong, because it's a definition. Take the expressions for momentum and total energy in natural units:misogynisticfeminist said:

[tex]

p=\gamma m_0 v

[/tex]

[tex]

E=\gamma m_0

[/tex]

If you want to define mass as the (Lorentz-invariant) norm of the 4-momentum, then [itex]m_0[/itex] is that mass. It doesn't change with velocity. On the other hand, there is nothing stopping you from associating [itex]\gamma m_0[/itex] together and

So, the only way to disprove relativistic mass is to disprove the associative property of real numbers under multiplication (it can't be done).

Maybe his name is DW. :rofl:pmb_phy said:Where did he get that idea from??

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I'll have to disagree with you on this point. Relativistic mass is defined such that the quantity mv is always conserved in collision (wherein one then defines the product mv as 'momentum'). Had nature been such that this is never measured in the lab then it would follow that the definition is incorrect in that it can't fit into what nature had in mind.Tom Mattson said:On the other hand, there is nothing stopping you from associating [itex]\gamma m_0[/itex] together anddefiningthat product as [itex]m[/itex]. This [itex]m[/itex] is called the relativistic mass, and it is a function of velocity.

So, the only way to disprove relativistic mass is to disprove the associative property of real numbers under multiplication (it can't be done).

Maybe his name is DW. :rofl:

Pete

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Daniel.

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Tom Mattson

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Is that not what I said? If you define [itex]\gamma m_0[/itex] as [itex]m[/itex], then [itex]p=mv[/itex] and [itex]E=m[/itex] (in natural units). These quantites are conserved.pmb_phy said:I'll have to disagree with you on this point. Relativistic mass is defined such that the quantity mv is always conserved in collision (wherein one then defines the product mv as 'momentum').

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Tom Mattson

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I'm not sure I get what you are saying. [itex]E[/itex] and [itex]m[/itex] are only identical in natural units. In the SI system, they have different dimensions.dextercioby said:Tom,since "c" is absolute (and NOT BECAUSE IT IS CONVENTIONALLY TAKEN AS "+1"),one should not speak about RELATIVISTIC MASS,but about ENERGY...

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Daniel.

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What pat of it are you confused about?dextercioby said:There's no need to introduce RELATIVISTIC MASS (a rather confusing concept,

Relativistic mass is defined differently than energy. Under certain cercumstances one is proportional to the other, I.e. E = -mc^2. It appers to me that you're asserting that the "m" in m = E/c^2 is identical to the "m" in m = p/v. If so then the assertion is incorrect since, in the general, E/c^2 does not equal m = p/v....at least to the unfamiliar with subtleties of SR/GR),when u have alreadyenergy...

Pete

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chroot

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Daniel.

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Okay,Warren,i'll back off.

Daniel.

Daniel.

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I was saying that relativistic mass is defined such that mv is a conserved quantity. What you posted implied that the definition cannot be wrong. What I posted was why a definition can be wrong. Its a fine point though and not worth worrying about.Tom Mattson said:I'm not sure I get what you are saying. [itex]E[/itex] and [itex]m[/itex] are only identical in natural units. In the SI system, they have different dimensions.

Pete

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Tom Mattson

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I get you. What I should have said was:pmb_phy said:I was saying that relativistic mass is defined such that mv is a conserved quantity. What you posted implied that the definition cannot be wrong. What I posted was why a definition can be wrong. Its a fine point though and not worth worrying about.

Naturally, relativistic mass would be falsified if SR were falsified.

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