seriously disabled Posted August 23, 2009 Share Posted August 23, 2009 What is second cubed s^3 as in the wikipedia article? http://en.wikipedia.org/wiki/Volt Link to comment Share on other sites More sharing options...
ajb Posted August 23, 2009 Share Posted August 23, 2009 [math]seconds \times seconds \times seconds[/math] as in units of time. Link to comment Share on other sites More sharing options...
seriously disabled Posted August 23, 2009 Author Share Posted August 23, 2009 [math]seconds \times seconds \times seconds[/math] as in units of time. I know but what does it mean? Link to comment Share on other sites More sharing options...
ajb Posted August 23, 2009 Share Posted August 23, 2009 I know but what does it mean? mean in what sense? It is there because a volt is a SI derived unit. Link to comment Share on other sites More sharing options...
seriously disabled Posted August 23, 2009 Author Share Posted August 23, 2009 mean in what sense? It is there because a volt is a SI derived unit. I still don't get what the physical meaning of cubic second is. Link to comment Share on other sites More sharing options...
ajb Posted August 23, 2009 Share Posted August 23, 2009 It comes about because of the definitions and fundamental units. I would not think of it as "a cube in time" if that is what you mean. Link to comment Share on other sites More sharing options...
seriously disabled Posted August 23, 2009 Author Share Posted August 23, 2009 It comes about because of the definitions and fundamental units. I would not think of it as "a cube in time" if that is what you mean. So how should I think of this? Link to comment Share on other sites More sharing options...
ajb Posted August 23, 2009 Share Posted August 23, 2009 I'd think of it as "book keeping". I don't know if anyone else here has different ways to think of things like this. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted August 23, 2009 Share Posted August 23, 2009 It is common in the inverse. velocity in meters per second acceleration in meters per second squared or per second per second jerk (change in acceleration) in meters per second cubed or per second per second per second Link to comment Share on other sites More sharing options...
seriously disabled Posted August 23, 2009 Author Share Posted August 23, 2009 It is common in the inverse. velocity in meters per second acceleration in meters per second squared or per second per second jerk (change in acceleration) in meters per second cubed or per second per second per second Oh nice. Now you made it clear to me. Thanks! Link to comment Share on other sites More sharing options...
Mudbird Posted February 7, 2010 Share Posted February 7, 2010 How would you use this in a kinematic equation? For example if height (x) is given by a constant times seconds-cubed, and an object is dropped from height x at time t, how do you figure out its falling time? If acceleration is not constant, then what is it? Thanks. Link to comment Share on other sites More sharing options...
Bignose Posted February 12, 2010 Share Posted February 12, 2010 How would you use this in a kinematic equation? For example if height (x) is given by a constant times seconds-cubed, and an object is dropped from height x at time t, how do you figure out its falling time? If acceleration is not constant, then what is it? Thanks. I think that what you are asking here is imprecise. However, if you are asking how, if given a specified jerk, how would you find the position as a function of time? You would integrate the jerk with respect to time three times. You will need 3 initial/boundary conditions. velocity = [math] v = \frac{dx}{dt}[/math] acceleration = [math] a = \frac{dv}{dt} = \frac{d}{dt} \frac{dx}{dt}[/math] jerk = [math] j = \frac{da}{dt} = \frac{d}{dt} \frac{d}{dt} \frac{dx}{dt}[/math] Link to comment Share on other sites More sharing options...
CaptainPanic Posted February 12, 2010 Share Posted February 12, 2010 The second x second x second in itself means very little. But in combination with other things it can be useful, like Bignose explained in the post just above this one. Typically, the second x second x second, and all kinds of other weird units are found in constants and in intermediate solutions or derivations. The final outcome of any calculation will be something tangible again. Take for example the Stefan-Boltzmann constant: [math]\sigma = 5.670 400(40) \times 10^{-8}\ \textrm{W}\,\textrm{m}^{-2}\,\textrm{K}^{-4}.[/math] It has weird units that mean little to me. If you take the unit apart and only look to he Kelvin to the power 4, it means even less. But in combination with a formula, it is correct and necessary. Link to comment Share on other sites More sharing options...
swansont Posted February 12, 2010 Share Posted February 12, 2010 The second x second x second in itself means very little. But in combination with other things it can be useful, like Bignose explained in the post just above this one. Typically, the second x second x second, and all kinds of other weird units are found in constants and in intermediate solutions or derivations. The final outcome of any calculation will be something tangible again. Take for example the Stefan-Boltzmann constant: [math]\sigma = 5.670 400(40) \times 10^{-8}\ \textrm{W}\,\textrm{m}^{-2}\,\textrm{K}^{-4}.[/math] It has weird units that mean little to me. If you take the unit apart and only look to he Kelvin to the power 4, it means even less. But in combination with a formula, it is correct and necessary. Right, because it turns out that radiation heat transfer scales with T^4. Nonlinear processes will often end up having constants with weird units. Context is everything. (I like the S-B, because it's easy to remember. 5678) Link to comment Share on other sites More sharing options...
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