# Application of 7th Derivative

1. Nov 9, 2004

### kristijo

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.

2. Nov 10, 2004

### Kurdt

Staff Emeritus
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

Last edited by a moderator: Nov 11, 2004
3. Nov 10, 2004

### Jenga

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?

4. Nov 10, 2004

### jcsd

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')

5. Nov 11, 2004

### cepheid

Staff Emeritus
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:

6. Nov 11, 2004

### Sirus

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.

Last edited: Nov 11, 2004
7. Nov 11, 2004

### Nylex

You mean 2nd.

8. Nov 11, 2004

### Sirus

Yes, sorry.

9. Nov 11, 2004

### Integral

Staff Emeritus
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.

Last edited: Nov 11, 2004