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Brain Storming - Time and Distance

  1. Mar 17, 2005 #1
    Many physical constant can be expressed in terms of Energy, Time [T] and Distance [L].

    Now some basic qestions for a brain storming session.

    1. if acceleration is L/T^2 then what name would you give the next term L/T^3 ?

    2. if the speed of light is the maximum speed is there also a limit to the acceleartion L/T^2, L/T^3 and L/T^4 etc.

    3. if frequency is 1/T then what is and what name would you give 1/L ?

    4. similarly has inverse speed T/L or better T/L^2 any physical meaning, or am I just stretching my abstract mind a bit too far.

    regards and have fun
  2. jcsd
  3. Mar 17, 2005 #2


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    1. Change in speed is acceleration, change in acceleration is jerk, change in a jerk is a snap, change in a crackle, change in a crackle is a pop. Those silly physicists... spagettification, branes, swiss meatballs, cereal related technical names...

    And in England a jerk is also referred to as something else I believe, but its more common to say its a jerk.
    2. Yes, of course relatively.
    3. Speed, I would say. 1 something per time amount, lets say second. That sounds like Frequency. 1 something per distance unit, that sound like speed.
    4. Well, pretty much everything has a physical meaning, including inverse acceleration. Just look at teh 336,000 results I got on google.
    Last edited: Mar 17, 2005
  4. Mar 17, 2005 #3
    1) I beleive it's called Jerk, like jerking a rope.
    2) There is NO upper limit to acceleration.
    3) 1/L -> Wavenumber is the closest concept I think.
    4) You can always make a situation where it is assigned
    physical meaning.

    Keep stretching. You're doing well.
  5. Mar 17, 2005 #4
    Acceleration is not limited, feel free to accelerate at a trillion meters per second /second (for a time far shorter than a second, of course).

    If we believe in time as passing at an absolute rate, it is obvious why we would measure distance L relative to a standard T. Because of special relativity, it is speed that is absolute (neither distance or time pass at an absolute rate) so we can convert meters equivalently to seconds.
    Last edited: Mar 17, 2005
  6. Mar 17, 2005 #5
    No the derivative of acceleration is surge, then its jerk I am not aware what the 5th derivative of position is.
  7. Mar 17, 2005 #6


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    Interesting, these signs made me think:

    if the sum of all the momentums is conserved (m/s)
    and the sum of all energies is conserved (m/s)^2
    can we deduce that the sum of all (m/s)^3 is conserved? I suppose I should probably just try a few problems and see if the before/after match up after solving using momentum and energy conservation.
  8. Mar 18, 2005 #7
    According, to http://www.absoluteastronomy.com/encyclopedia/d/de/derivative.htm [Broken] jerk IS the first derivative of acceleration. No one really cares what the rest are, theres a point where it's only used for math anyway, and doesn't get applied.

    Oh, and to #3, I would call it inverse distance.
    Last edited by a moderator: May 1, 2017
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