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What known equations have units s²/m² ?

  1. Aug 13, 2013 #1
    I invented a weird equation using a substitution that ends up with units of s²/m².

    I have an idea of what I'm looking and what the value implies but I could use examples of other know equations that use s²/m².
  2. jcsd
  3. Aug 13, 2013 #2


    Staff: Mentor

    Pretty much any equation with a v or c could be rearranged to give units of s^2/m^2.

    E=mc^2 -> m/E=1/c^2


    It's a rather trivial exercise, but could be done all over.
  4. Aug 14, 2013 #3
    The units of speed or velocity (v) are m/s which means that the quantity v2 has units
    m2/s2 so the units you came up with in your exercise are units of 1/v2
  5. Aug 14, 2013 #4
    Thanks for the reply. After posting yesterday I went looking through an old physics book and ran across J/(m²/s²) = (J)s²/m² = (kg m²/s²)s² / m² = kg m²/m² = kg. The (J)s²/m² shows Mass(kg) is energy in joules(J) when s²/m² is removed and the units match nicely with m=e/c² if m is replaced by e(?) for finding an equivalence of (?) m=e/c² substituting e(?) for m---> e(?)=e/c² ---> (?)=1/c²--->(?)=1/(300,000,000 m/s)²---> (?)=1.1-17 s²/m²
    Doesn't make any sense does it? It's not units for energy, mass, velocity, pressure, acceleration or anything generally recognizable as units of measurement but it is there. Why would squared time be divided by squared distance? We can see that the other part of mass (?) involves s²/m².
    Any more examples of equations that use s²/m² or even s/m?
  6. Aug 14, 2013 #5


    Staff: Mentor

    As I said, ANY equation with c or v can be rewritten that way. Those units are just (1/speed)^2. There is nothing particularly unusual or surprising about them. Just solve any equation for v or c, then invert and square.
    Last edited: Aug 14, 2013
  7. Aug 14, 2013 #6
    I agree that most people who have an interest in physics have seen them.

    Just an inversion for the use of equations. Not some kind of description of part of what makes mass. The only other imaginable thing I could think of that might use...that is beyond the scope of these forum.
  8. Aug 14, 2013 #7


    Staff: Mentor

  9. Aug 15, 2013 #8
    you sure?

    You know that solid? No possible way it could mean anything?

    s²/m² is t²/d². d² is usually seen as area. What could t² mean second per second...I have some understanding and I believe I found a meaning of t² so that t²/d² can be made usable and recognizable. Possibly in a way that Einstein saw it.

    Surely someone else has an idea.
    Last edited: Aug 15, 2013
  10. Aug 15, 2013 #9


    Staff: Mentor

    Correct. Meaning is not extracted from the units. It is extracted from the equation.

    You can always make an equation use any units you like, simply through algebra, without changing the physical meaning at all. There is nothing inherently meaningful about any particular combination of units itself.
  11. Aug 15, 2013 #10
    That doesn't make sense

    That doesn't make sense. Time and distance are the fundamental building blocks.

    Are you suggesting everyone should just do away with SI units?

    Here's a good one http://physics.nist.gov/cuu/Units/SIdiagram.html and illustrates what I'm talking about. Looks to me as though there are a few missing and possibly undiscovered names for derived units.

    Links to other derived units.

    Seriously wishing I were a billionaire to devote substantial contributions to Wikipedia type sites to proliferate more and better information with detailed history of statements, authors and in-depth timelines included.
  12. Aug 15, 2013 #11


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    You need to learn how to comprehend better. No one is arguing of doing away with these units. Rather, what YOU are doing, in which you simply manipulate these units however you please IS the one that is meaningless, because you are ignoring the physical parameters that are associated with these units. I simply cannot take a quantity and simply multiply and divide however I please without understanding the PHYSICS of the operation! That is what you have ignored and made this rather puzzling.

  13. Aug 15, 2013 #12

    I agree that I could use better comprehension and the same could be said for everyone.

    I have an understanding so I looked at mass equations and spotted where it could be applied.
    Physics brought me to take a closer look at t²/d² as being an element of mass with energy removed. The concept I'm looking at is difficult for everyone and I can not mention it on the forum because it is against the rules so I do not. I'd like to share the idea here in the midst of others interested in physics but it is against the rules.

    I posted on this forum asking for examples of equations that use s²/m² but I didn't get anything beyond what I've seen. I did get responses along the lines of "trivial" and a response that amounts to "it's just an inversion of velocity". I was hoping to run across someone very well versed in a broad range of equations using SI units. Particularly the ones with s²/m² in them.

    I was hoping for more examples. Search engine results do not find s²/m² very well. I looked at the units closer as t²/d². d² is generally understood as area. But t² or second per second. I can only see as having two possible meanings in relation to being "per area" that would fit with my understanding and be allowed on this forum.
    I'd write what it is I'm talking about but that would probably be against the rules. So I guess now all I'm after is just examples of t².

    One part of physics is a puzzle that I've been considering for many years and have learned to visualize.
  14. Aug 15, 2013 #13


    User Avatar

    Staff: Mentor

    Nowhere on the internet will you find a collection of people (professional scientists and engineers) better versed in it than here. But frankly, expertise isn't needed here: this is an introductory level issue (understanding how to properly manipulate equations and units and what it means when you do).
  15. Aug 15, 2013 #14


    Staff: Mentor

    We appreciate your keeping within the rules. Since this topic seems impossible to discuss productively within the rules the thread is closed. You have been given accurate and complete information within mainstream science.
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