Dots on physics equations. What do they mean?

[epislon58]

So when there is a dot above the equation it means with respect to time. What does it mean if there are two on the top or one on the side?

 

[mfb]

Two on top of a variable usually mean the second derivative with respect to time.
"One on the side" - can you give an example?

 

[ZapperZ]

So when there is a dot above the equation it means with respect to time. What does it mean if there are two on the top or one on the side?

For future reference, always provide context and sources when you ask something like this.

Zz.

 

[256bits]

That is a shorthand of writing the derivative. Two dots above would mean double derivative.

One on the side - I don't recall that one.

PS. 0405, 0406, 0408 and they all showed up with my post not before

 

[Nugatory]

So when there is a dot above the equation it means with respect to time. What does it mean if there are two on the top or one on the side?

One dot on top usually means the first derivative with respect to time (that is, speed), two dots on top the second derivative with respect to time (that is, acceleration).

A dot on the side? Show us an example of what you mean and you'll get a better answer.

 

[256bits]

perhaps the dot on the side - he is referring to f prime and f double prime - only thing i can think of, only it's not a dot.

 

[epislon58]

This is what I am talking about.

 

[mfb]

I think that is a punctuation mark. Or a misplaced time-derivative point.

 

[epislon58]

Well it so the Euler Lagrange equation. Is it suppose to be there ?

 

[mfb]

That's hard to tell from the RHS only, as both derivatives (with and without dot) are interesting.
You can check the units to find it out.

 

[epislon58]

This is the entire equation

 

[mfb]

That is a punctuation mark.

 

[epislon58]

Thank you good sir.

 

[namanjain]

it's just derivative wrt time


.
x = dx/dt
= lim: t→0 in x/t

 

[CompuChip]

namanjain, OP is talking about the second dot.
That's just a period marking the end of the sentence.

 

[namanjain]

namanjain, OP is talking about the second dot.
That's just a period marking the end of the sentence.

ohh! sorry read half of the first sentence
well 2 on top means: ..
x =
d²x
______________
dt²

second derivative

eg if
x=t⁸ e^(t2)

a = d²x
______________
dt²

get answer using wits,( it's short)

aNs

a= 56t⁶e^(t2) + 34t⁸e^(t2) 4t¹⁰e^(t2)

 

[mfb]

namanjain please read the full thread, you are not adding anything new here.

 

[namanjain]

namanjain please read the full thread, you are not adding anything new here.

then i suppose discussion is over, thank you

 

[Borek]

Over means over, thread closed.