# Do photons have inertia?

Discussion in 'Physics & Math' started by Literphor, Apr 5, 2012.

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1. ### LiterphorI is for ignoranceRegistered Member

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I couldn't find a clear answer to this question, so please enlighten me. My understanding right now is it does not.

3. ### AlexGLike nailing Jello to a treeValued Senior Member

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They have no inertia, because they are massless. They do have momentum, a measure of energy, which is independent of mass.

5. ### Big ChillerRegistered Senior Member

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@AlexG

Mass is a form of energy, just saying.​

7. ### AlexGLike nailing Jello to a treeValued Senior Member

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No.

Mass is equivalent to energy, but that's not saying they're the same thing.

8. ### Big ChillerRegistered Senior Member

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@AlexG

I'll say it clearer for you then mass is a form of energy there are other forms energy such as electromagnetic radiation but electromagnetic radiation and mass are NOT the same thing, they are all classed under energy.​

9. ### AlexGLike nailing Jello to a treeValued Senior Member

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Then let me say it clearer to you.

You're wrong.

Mass and energy are not the same things, thay are not all classed under energy. There is an equivalence of mass and energy, but they're not the same things.

Is that clear enough?

10. ### Big ChillerRegistered Senior Member

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@AlexG

I of course disagree with your comment according to mainstream understanding. Equivalence of mass-energy is just a technical phrase it's really equivalence of electromagnetic radiation-mass.​

Last edited: Apr 5, 2012
11. ### AlexGLike nailing Jello to a treeValued Senior Member

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And I, of course, continue to disagree with yours.

12. ### Big ChillerRegistered Senior Member

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@AlexG

Your disagreement is backed by what?​

13. ### originHeading towards oblivionValued Senior Member

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Mass and energy are not the same thing.

$E \not= M$

There is an equivilancy:

$E = Mc^2$

Force:

$F = ma$

$F\not=Ea$

14. ### Big ChillerRegistered Senior Member

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@origin

Note the equivalency in the famous equation is between electromagnetic radiation (not energy) and mass in actuality.​

15. ### James RJust this guy, you know?Staff Member

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Sorry, but that's wrong.

$E=mc^2$ says that any object with mass $m$ can, in principle, be converted into an amount of energy $E$, or vice-versa. There is no restriction to electromagnetic radiation.

16. ### Big ChillerRegistered Senior Member

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@James R

All I'm saying is that E which represents energy in physics is electromagnetic radiation and that in actuality both electromagnetic radiation and mass are forms of energy.​

Last edited: Apr 5, 2012
17. ### James RJust this guy, you know?Staff Member

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There are other forms of energy other than electromagnetic energy, Big Chiller. The symbol E is often used for these other forms of energy.

18. ### Big ChillerRegistered Senior Member

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@James R

Agreed and also mass is one of those forms but is distinguished from the other forms by the symbol E.

19. ### AlexGLike nailing Jello to a treeValued Senior Member

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Nope. It's already been pointed out that there are other forms of energy besides em, and mass is not a form of energy.

You seem to think that 'equivalence' means 'the same thing as".

20. ### Big ChillerRegistered Senior Member

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@AlexG

It's your assertion against my logical claim and fyi I don't think *equivalence* means the same thing as.​

Last edited: Apr 5, 2012
21. ### AlexGLike nailing Jello to a treeValued Senior Member

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Ah, logic.

Science works better.

Try it sometime.

22. ### Big ChillerRegistered Senior Member

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@AlexG

Excellent, deny all logic and rationality that scientific method is founded on as well as sidetrack from what was being discussed.​

23. ### BWE1Rulers are for measuring.Registered Senior Member

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Photons don't have inertia but they do have momentum.