Question About Mass

Discussion in 'Physics & Math' started by OilIsMastery, Nov 30, 2008.

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  1. OilIsMastery Banned Banned

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    Q: Is it possible for something with no mass to move something that has mass?
     
  2. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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  3. OilIsMastery Banned Banned

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    Can you say more please? How? Can you give an example? Scientific reference? Link?
     
  4. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Before you ask: conservation of momentum.
     
  5. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Before you ask: yes, photons have momentum.
     
  6. OilIsMastery Banned Banned

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    How is that possible?

    p=mv right?

    So momentum for a so-called "massless" photon would be p = 0 x c = 0.
     
  7. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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  8. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    No. Learn physics.

    For a photon, p = h f / c, where h is plack's constant, f is the frequency of the wave, and c is the speed of light.
     
  9. OilIsMastery Banned Banned

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  10. OilIsMastery Banned Banned

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    So physicists rewrote the momentum equation for the photon?
     
    Last edited: Nov 30, 2008
  11. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    There is no conservation of mass.
     
  12. OilIsMastery Banned Banned

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  13. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Do you read your own references?

     
  14. OilIsMastery Banned Banned

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    Why did physicists rewrite the momentum equation for photons?
     
    Last edited: Nov 30, 2008
  15. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    State the law of conservation of momentum, please.
     
  16. OilIsMastery Banned Banned

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    p=mv?
     
  17. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    how does one see conservation of momentum from this statement?
     
  18. OilIsMastery Banned Banned

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    I don't know. I'm supposed to be the ignorant one. I came here asking the questions. I didn't come here asking questions because I have answers.

    One of my questions is, why did physicists change and rewrite the momentum equation p=mv for photons?
     
  19. Trippy ALEA IACTA EST Staff Member

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    Here's a clue (because this is painful, like watching a fish gasping and flopping in the bottom of a boat).

    p=mv doesn't state the conservation of momentum.
    It's the clasically derived equation for calculating the momentum of a massive body.
    It's a special case of a broader equation that is valid only in a small set of situations.
     
  20. OilIsMastery Banned Banned

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    Great, that doesn't answer my questions so thanks for nothing.
     
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