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Whenever we increase the velocity of a particle, the mass of he particle also

  1. Sep 5, 2012 #1
    I read somewhere than whenever we increase the velocity of a particle, the mass of he particle also increases. I also read that it is impossible reach the speed of light as the mass of the particle, just before reaching the speed of light, will become infinite (not infinite but very large) and a lot of force will be needed to increase the speed further which will only result in more increase in mass. Now, i have the following 2 questions-

    1. Why do mass go on increasing? and-
    2. what if we consider mass less particles? Which there will an increase in mass too? If no, then why cant they achieve the speed of light?
  2. jcsd
  3. Sep 5, 2012 #2


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    Gold Member

    Re: Please see below-

    Hey, welcome to the forum. I would suggest that in future you think of a meaningful title for your posts, since that way you will attract more people who are interested in the subject you are asking about. "Please see below" is not helpful.

    Massless particles ALWAYS travel at the universal speed limit (the same speed that light travels at).
  4. Sep 5, 2012 #3

    Doc Al

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    Staff: Mentor

    Re: Please see below-

    Massless particles (particles with zero invariant mass) already move at the speed of light.
  5. Sep 5, 2012 #4
    The answer to your first question should answer an important distinction: the real mass of the particle is not increasing.

    There is a danger of equivocation over 'equivalence' and 'sameness' in Einstein's famous equation. What is increasing is the total energy of the system. By analogy, we can say that dollar and a yen can be related in an equation (using the exchange-rate as a constant). But a dollar is not a yen.
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