PDA

View Full Version : Application of 7th Derivative


kristijo
Nov9-04, 08:36 PM
PLEASE HELP!!!

Does anyone know the use of the 7th derivative of a position function? I know the first is velocity and the second acceleration, and the third is jerk. But what is the real work application for the 7th derivative.

Kurdt
Nov10-04, 06:16 AM
That would be the rate of change of pop. Don't believe me well take a look here


Edit:

This is not common usage.

Integral

Jenga
Nov10-04, 07:54 PM
Huh, this is new to me. Since when is there any use of a "practical" name for anything higher than the 3rd derivative of position? Sure they can be useful, but why bother assigning misleading nomenclature?

jcsd
Nov10-04, 08:07 PM
The forth deribavative is also of practical use, for example on a rollercosaster the fourth derivative will not be a constant function of time but the motion of a rollercoaster should be known with very high precsion (the motion of a rollercosater follows a very strict pattern, but the fact taht the higher derivatives of postion wrt time are not constant create the feeling that the motion of the rollercosater is 'out of control')

cepheid
Nov11-04, 01:52 AM
Kurdt, if you look at the end of the last paragraph of that document you linked to, the author states that they just made those names up on some usenet, which is a relief. I find it hard to believe that snap, crackle, and pop would ever become standard terminology. Besides, I thought whimsical names were only allowed in quantum mechanics :rofl:

Sirus
Nov11-04, 12:38 PM
Derivatives give slope, or rate of change with time. Acceleration (3rd derivative of displacement) gives rate of change of velocity, but if velocity is not changing at a constant rate, we apply 4th derivative. If acceleration is not changing at a constant rate, we apply 5th, and so on.

Nylex
Nov11-04, 12:53 PM
Acceleration (3rd derivative of displacement)

You mean 2nd.

Sirus
Nov11-04, 12:58 PM
Yes, sorry.

Integral
Nov11-04, 04:34 PM
I think that this thread has run its course. I am not happy with a link to a practical joke which can be taken as meaning physics by someone not familiar with the facts. While you can assign names to any derivative of anything you wish, the fact is that only the first three time derivatives of displacement have commonly used names.

They are

\dot {x} = \mmbox{Velocity}

\ddot {x} = \mmbox{Acceleration}

\dddot {x} = \mmbox {Jerk}

With that said I am going to edit out the link to the joke in this thread. If someone wants to repost it in the joke thread, please feel free. It does not belong in this fourm.