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Thread: light and time

  1. #1 light and time 
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    Hey i am
    investigating into the whole time and light thing.
    I watched something on TV about the formula E=MC2 (Energy=Mass*speed of light to the power of 2) and it said that as the velocity of an object accelerated the mass increased. So my question is if you had a space ship in space (a vacuum) where there where no extra particles apart from the ship then would the mass of the ship increase as it's velocity increases? If not then surely it would be possible to build an engin that would be able to run at a unbalievable speed and not have any effect on the mass of the object?



    Its not whats on the out side that we observe closer
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  3. #2  
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    if i know what i'm talking about then i can tell you.

    a spaceship can only go so fast of a givin amount of fuel.
    if we want it to go faster we need to add more fuel which means the spaceship will gain mass and it will be harder to push, infact you would need to add an infinite mass to make it go at the speed of light.

    if you put the ship in a vacuum then there would be no way to add fuel or mass so the spacecraft would only go at the highest speed it can obtain with the amount of fuel mass it has.

    i guess in this way i guess scientists reasoned that an object travelling at the speed of light won't have any mass.


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  4. #3 Re: light and time 
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    Quote Originally Posted by ssj4dave
    So my question is if you had a space ship in space (a vacuum)
    This is not a potentially real condition, and is irrelevant to the argument at hand.

    where there where no extra particles apart from the ship
    What is this? What other particles might you be referring to?

    then would the mass of the ship increase as it's velocity increases?
    The conditions that you suggest, even though not a realistic scenario, would nevertheless be part of the theory that you question, and would not be able to sidestep it. I don't really understand what about the scenario that you propose might possibly be considered to be able to by pass the theory of relativity. Do you?
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  5. #4  
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    what i ment is:
    Imagin there is an object in a vacume, as you increase the speed in which the object travels would the mass still grow because there is nothing to effect the object if it is in a vacume? Or is it that the speed its self is the effector and that is the thing that increases the mass?
    Its not whats on the out side that we observe closer
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  6. #5  
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    Quote Originally Posted by ssj4dave
    Imagin there is an object in a vacume,
    I see no reason to imagine an impossible situation. The fact that you place an object within this hypothetical vacuum should alone serve to indicate that it is not a vacuum.

    as you increase the speed in which the object travels would the mass still grow because there is nothing to effect the object if it is in a vacume?
    Even if this hypothetical vacuum were to exist, it would be irrelevant. You seem to be willing to ignore the fact that the entire visible universe would still be exerting a gravitational effect on the object. Of what relevance would a vacuum be?

    Or is it that the speed its self is the effector and that is the thing that increases the mass?
    This is a complex question, and is not easy to answer. You might examine a site on the Internet such as http://math.ucr.edu/home/baez/physic...y/SR/mass.html for some insight.
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  7. #6  
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    yea thanks for the site
    just one thing in future could you try to sound a bit happier in your replies i mean i am only GCSE level and do not know as much as most people here so i am haveing to learn and change my understanding k?
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  8. #7  
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    Quote Originally Posted by ssj4dave
    i mean i am only GCSE level and do not know as much as most people here so i am haveing to learn and change my understanding k?
    Which makes you, what 16-ish? Then you are doing very well!

    Unfortunately, you are asking questions whose answers you may not understand - certainly I wouldn't have understood at your age. Just keep plugging away at that calculus, that's the key!
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  9. #8  
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    thanks
    Its not whats on the out side that we observe closer
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  10. #9  
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    Quote Originally Posted by ssj4dave
    in future could you try to sound a bit happier in your replies i mean i am only GCSE level
    I can try. What is GCSE?
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  11. #10  
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    [quote="Hermes"]
    What is GCSE?
    It is the exam taken in the UK upon completion of the minimum educatioal period required by law. It is usually taken at age 16 or so, and is rather general in it's scope.

    daveThe important thing to know is that the mass of your spaceship only increases relative to somebody looking at it from the outside. The crew experience no such increase (that's why the theory of which E = mc<sup>2</sup> is a part is called Relativity)
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  12. #11  
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    ah i see now it is beggining to make sence to me thnks all
    (posting this from goonhilly satalit station!!!!)
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  13. #12  
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    Quote Originally Posted by ssj4dave
    what i ment is:
    Imagin there is an object in a vacume, as you increase the speed in which the object travels would the mass still grow because there is nothing to effect the object if it is in a vacume? Or is it that the speed its self is the effector and that is the thing that increases the mass?
    It is the velocity itself that causes the mass increase; the space ship wouldn't need to interact with any other particles in space for the effect to occur. The apparent mass of the ship for purposes of calculating acceleration would be:

    mass = rest mass / [1- (velocity/C)^2]

    Notice that as the velocity gets close to C, the mass will approach infinity, meaning that the energy needed to accelerate the ship would approach infinity.
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