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General Forums => The O' Club => Topic started by: Tac on November 20, 2008, 09:06:23 PM

Title: Seeking definition : math related
Post by: Tac on November 20, 2008, 09:06:23 PM
Radial velocity is the rate at which one or 2 objects approach or move apart from each other (aka the old 2 trains on collision course).

I'm trying to find out if there is a similar measurement that will tell the user that both objects are in fact running towards each other and not apart. As in a negative radial velocity means closing in, positive radial means moving apart.

I need to find out if there is a measurement specifically for TWO objects (not one, not three.. two) that would tell the user if moving closer it will be a negative number and apart a positive number.


Its a long shot but I wonder if you guys know any (if any exist).
Title: Re: Seeking definition : math related
Post by: oakranger on November 20, 2008, 09:24:27 PM
physics? not my cup of tea.
Title: Re: Seeking definition : math related
Post by: moot on November 20, 2008, 09:29:30 PM
What is this for?  Documentation, or programming, or..?
Title: Re: Seeking definition : math related
Post by: Tac on November 20, 2008, 11:11:11 PM
was fiddlin' with some stuff. found it I think. Relative Velocity.

 :P
Title: Re: Seeking definition : math related
Post by: Meatwad on November 20, 2008, 11:13:06 PM
Yeah thats them big fancy words

Around here, negative radial velocity means its comin at'cha and get yer butt outta the way

positive radial velocity means yer tractor is runnin off without'cha

Title: Re: Seeking definition : math related
Post by: Chalenge on November 21, 2008, 12:53:30 AM
positive radial velocity means yer wife is runnin off without'cha

Fixed  :D
Title: Re: Seeking definition : math related
Post by: bozon on November 21, 2008, 02:50:14 AM
Radial velocity is the rate at which one or 2 objects approach or move apart from each other (aka the old 2 trains on collision course).

I'm trying to find out if there is a similar measurement that will tell the user that both objects are in fact running towards each other and not apart. As in a negative radial velocity means closing in, positive radial means moving apart.

I need to find out if there is a measurement specifically for TWO objects (not one, not three.. two) that would tell the user if moving closer it will be a negative number and apart a positive number.


Its a long shot but I wonder if you guys know any (if any exist).
I am sorry but I fail to understand your question.

The most common way to measure radial velocity is by using the Doppler effect. You shoot a signal with some frequency related to it (wave, series of pulses etc.) at the other object and measure the frequency in the returned signal - This is how radars and lasers are used to measure radial velocity. The other option is to use a signal of known frequency emitted by the other object and measure it frequency when it reaches you - this is how radial velocities are measured in astronomy. The ratio between the "original" and received frequencies is a function of the relative radial velocity. The exact formula depends on the case (returned signal, source emitted signal, sound wave, light etc.).

The positive/negative value of the velocity is just a matter of definition and may be confusing. This is why "blue shift" and "red shift" are commonly used to describe "approaching" and "receding" objects instead.

By the way, an object with a radial velocity toward you does not necessarily mean it is on a collision course.
Title: Re: Seeking definition : math related
Post by: Dragon on November 21, 2008, 12:59:04 PM
Radial velocity - 1.(n) The forward or backward motion as measured and interpreted by the speedometer.  2. (n) The quantity of rotations multiplied by the vector of the wheels on the bus as they go round and round. 

   
Title: Re: Seeking definition : math related
Post by: kamilyun on November 21, 2008, 08:13:22 PM
What is this for?  Documentation, or programming, or..?

He's developing an aimbot  ;)
Title: Re: Seeking definition : math related
Post by: Shuffler on November 22, 2008, 02:31:38 PM
Where did the first object come from and where is it going? Now what about the second object? Did either bring the kids or are they alone? What altitude...... I need some input to work on this simple process.....


Oh yes... what color is the first object... this is not necessary for the second object for obvious reasons.


BTW is one named Willy? I hear he goes round n round in circles..... and he flies high like a bird up in the sky... oh ohhhh...
Title: Re: Seeking definition : math related
Post by: bcadoo on November 22, 2008, 11:34:43 PM

I need to find out if there is a measurement specifically for TWO objects (not one, not three.. two) that would tell the user if moving closer it will be a negative number and apart a positive number.


Its a long shot but I wonder if you guys know any (if any exist).

Umm..isn't it called distance?
Title: Re: Seeking definition : math related
Post by: drdeathx on November 24, 2008, 02:59:59 AM
(http://i435.photobucket.com/albums/qq77/AAdeath/ab80229024033a9a.jpg)



This is how I measure!!!



 :rofl