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Thread: About the formula for density and mass

  1. #1 About the formula for density and mass 
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    Density is mass divided by volume


    But then mass is volume times density, but density is mass divided by volume


    Let Volume be x,
    mass is y,
    density is z


    Then z = y / x


    And y = x * z but z is y / x then it turns out y = x * y / x or xy / x, we reduce and it turns out y = y, which is mass = mass and no matter what volume is, the mass will not change.


    It should be clarified that this is a rest mass


    Or have I made a mistake somewhere?


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  3. #2  
    Bullshit Intolerant PhDemon's Avatar
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    You just appear to be bewildered by basic algebra...

    It should be blatantly obvious that y=y...


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  4. #3  
    exchemist
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    Quote Originally Posted by Anffaeledig View Post
    Density is mass divided by volume


    But then mass is volume times density, but density is mass divided by volume


    Let Volume be x,
    mass is y,
    density is z


    Then z = y / x


    And y = x * z but z is y / x then it turns out y = x * y / x or xy / x, we reduce and it turns out y = y, which is mass = mass and no matter what volume is, the mass will not change.


    It should be clarified that this is a rest mass


    Or have I made a mistake somewhere?
    Well of course you get y=y if you do what you have done.


    Think: if I spend some money M to get a number of oranges, N, I can write the price per orange P as M/N. And that means that M=N*P.

    So I can do the same thing as you did, viz. I can write M =N*(M/N) which reduces to M=M. Does that mean the money I have to spend does not depend on how many oranges I buy?
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  5. #4  
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    [QUOTE = exchemist; 632740] [QUOTE = Anffaeledig; 632735]
    (M / N)
    [/ QUOTE]

    hooks

    (this is me and my mind)
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  6. #5  
    exchemist
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    Quote Originally Posted by Anffaeledig View Post
    [QUOTE = exchemist; 632740] [QUOTE = Anffaeledig; 632735]
    (M / N)
    [/ QUOTE]

    hooks

    (this is me and my mind)
    Yes, it is.
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