Speed vs. Velocity

[CajunCenturion]

The thread discussing the differences between precision and accuracy reminds me of a similar discussion, where again, the scientific meanings of the terms, and the perceived meanings of the terms, may be different.

What is the difference between speed and velocity?

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[sleipnir214]

Velocity is a speed in a direction.



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[fumei]

Does that mean you can have speed in NO direction? In ALL directions? Well actually, you can have speed in all directions if you have a shell expanding spherically. In fact, for a planetary nebula they do in fact measure shell velocity. Although it is, of course, never a smooth shell.

Gerry
My paintings and sculpture

 

[stackdump]

Exactly as sleipnir states, if you walked around in a circle and came back and stopped at the place you started from, your velocity is zero. But you would have had an average speed as you made that journey.

So velocity is how far you have travelled from your origin in a given time (so for the example above the distance travelled from the origin is zero).

Speed is the distance you actually travelled in a given time (that distance being the circumference of the circle).

 

[AnotherHiggins]

Velocity is basically speed with a vector (direction). It's been a long time since physics class, but as I recall

speed = ^{distance traveled}/_{time traveled}
[tab]whereas
velocity = ^{displacement from original location}/_time

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[blue]-John[/blue][/tt]
[tab][red]The plural of anecdote is not data[/red]

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[Golom]

Or to extend the "walking around a circle" thought ...

As you walk around the circle at a steady pace, your speed is constant (distance moved per unit of time) but your velocity is ever-changing because you move not just forward but also in a different direction with each step.

Of course, when you arrive back at your point of origin and stop then BOTH speed and velocity are zero.

 

[Gooser]

speed = ^{distance traveled}/_{time traveled}

Are you saying that time travel is possible?

[insert appropriate amount of sarcasm here]

v/r

Gooser

Why do today
that which may not need to be done tomorrow --me

 

[2ffat]

The difference is velocity always gave me nightmares in physics class and speed was easy to compute.

BTW, don't forget instantaneous velocity.

James P. Cottingham
-----------------------------------------
^{I'm number 1,229!
I'm number 1,229!}

 

[tsdragon]

And since velocity is apparently changing depending on the initial and current state, what does "net velocity" mean?


Tracy Dryden

Meddle not in the affairs of dragons,
For you are crunchy, and good with mustard.

 

[Gooser]

net velocity is how far a net has travelled from your origin in a given time?

v/r

Gooser

 

[Chacalinc]

from yourdictionary.com:

Speed:

# Physics. The rate or a measure of the rate of motion, especially: a. Distance traveled divided by the time of travel. b. The limit of this quotient as the time of travel becomes vanishingly small; the first derivative of distance with respect to time. c. The magnitude of a velocity.


velocity:

Physics. A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.


Hope this helps.

Chacal, Inc.

 

[SantaMufasa]

Given: From a starting point, one walks at a constant pace, in a circle with diameter 1 km.

1) Who can identify the point on the circle where the walker reaches her/his greatest velocity.

2) Who can assert a/the formula for representing the walker's (x:y) velocity curve while walking the circle?

Mufasa
(aka Dave of Sandy, Utah, USA)
[I can provide you with low-cost, remote Database Administration services: see our website and contact me via www.dasages.com]

 

[Scott24x7]

Gooser,
You board a plane at 9:45am in Sydney Australia on Friday 13 July, 2001. You fly for 14 1/2 hours. You land in Los Angeles 13 July, 2001 at 6:05am.

Yes, time travel is possible, as long as you're flying in the right direction.



Best Regards,
Scott

"Everything should be made as simple as possible, and no simpler."

 

[AnotherHiggins]

Given: From a starting point, one walks at a constant pace, in a circle with diameter 1 km.

1) Who can identify the point on the circle where the walker reaches her/his greatest velocity.

I've heard this one before.... The North Pole!!



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[blue]-John[/blue][/tt]
[tab][red]The plural of anecdote is not data[/red]

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[Gooser]

When the walker is walking due East, the walker reaches their greatest velocity.

v/r

Gooser

Why do today
that which may not need to be done tomorrow --me

 

[JediBMC]

Time travel is easy with a "Time And Relative Dimensions In Space" ship. Without that we can only travel through time zones, as the Zulu (GMT) time is always progressing.

-Brian-
Semper Paratus

 

[Golom]

Then there is the infamous airline announcement

In a few minutes we will be landing in <pick your favorite third-world city>
Please set your watches back 2,000 years.
​

 

[SilentAiche]

Personally, I find Tim travel very common. Hell, I go near about every morning. I might go even quicker if I ate Mexican the night before. "Montezooma's" revenge and all that. I estimate my outpoot using standard issue equipment, namely a peedometer and tacometer.

[red]:[/red]Tim[red]:[/red]

[gray]what, you thought I lacked the intestinal fortitude to include a subtle "colon" reference? [/gray]


[blue]_______________________________________________________
"Although many figures are strange, prime numbers are truly odd."[/blue]

 

[Gooser]

Speaking of which...

I think it's time to go truncate the log as we say in the database world.

v/r

Gooser

Why do today
that which may not need to be done tomorrow --me