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I Measured Values In Physics

  1. Feb 5, 2017 #1
    Are all physical quantities inherently positive?

    In mathematics, you have some order on the axis. -100 < -5 < 5 < 100.
    But in physics, a speed of -100 is larger than a speed of -5. The minus sign just shows the direction which is opposite of what we defined to be positive.
    Likewise, the energy. If we have a negative energy, it just means that we took energy out of the system. If we add energy, then it is positive.

    So it seems that all measured values are greater than 0. My question is. Are there physical quantities which are inherently negative? In a way that -100 of that quantity is smaller than -5. So in a way that the minus sign does not show something opposite of our convention, our reference system.
  2. jcsd
  3. Feb 5, 2017 #2


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    No. Physical quantities just exist, with no numerical measurement. Humans invent a numerical measurement and apply it. In early history, if something existed, humans measured it as positive. They didn't even invent negative numbers till later. So there is no inherent positive or negative to a physical quantity, it's a result of human nature.
  4. Feb 5, 2017 #3
    I agree. Thanks for answer.
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