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Velocity is a vector quantity.

Discussion in 'General Gun Discussions' started by zahc, Sep 28, 2004.

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  1. zahc

    zahc Member

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    Does it bother anyone else that projectile speed in the gun world is called velocity even though the only thing of interest is the speed?

    Who's gonna start calling it 'muzzle speed' or 'high speed .22s' instead of high velocity?
     
  2. Mal H

    Mal H Administrator

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    "Does it bother anyone ...?"

    Not me. :)

    Bullets generally go in one direction only, so we might as well call that a positive direction (vector).
     
  3. JohnBT

    JohnBT Member

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    The first definition in this dictionary says: 1. Rapidity or speed.

    The second one says: 2. Physics. A vector...

    John...I was a physics major once upon a time
     
  4. mete

    mete Member

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    When the bullet richochets off the rock and hits you the velocity[since it returned to it's original point] is zero but it does have speed .
     
  5. trapperjohn

    trapperjohn Member

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    i teach mechanical engineering, and have taught physics so I know what vectors are.

    Does it bother me? Not at all, not worth getting upset about in the least.
     
  6. GD

    GD Member

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    I figure mine to be velocities. Outgoing is positive, incoming is negative!:rolleyes:
     
  7. S Roper

    S Roper Member

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    Mass and force confusion bothers me a lot more.
     
  8. mondocomputerman

    mondocomputerman Member

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    The components of velocity are speed and direction. And yes I have thought of it before. And no, it doesn't bother me, unless the direction is towards me!
     
  9. 45crittergitter

    45crittergitter Member

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    Wrong. If it is still moving, it has speed and direction; therefore it has velocity.

    Also wrong. Dictionaries are notorious for getting technical definitions wrong. Basically anything moving has velocity, since velocity is a vector whose value or magnitude is speed and whose other component is direction.
     
  10. JohnBT

    JohnBT Member

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    But it's not a technical dictionary, it's an English dictionary. :neener:

    John
     
  11. boing

    boing Member

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    You know, we're still fighting an uphill battle with clips and magazines, and bullets and cartridges. One step at a time, okay, guys? ;)
     
  12. Bwana John

    Bwana John Member

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    Yes, you are correct. It turns out that velocities have more that just a size. They also have a direction. For example, a statement correctly stateing a velocity would say, "The velocity equals 25 meters per second North ." Notice that two things are necessary to state a velocity, as magnatude, that is, 25 meters per second, and a direction, North. This is how you talk about velocities when you are studying physics. The size of the velocity is called the speed. So, we would say that velocity is made up of a speed and a direction. Quantities like this, that have magnatudes and directions, are called vectors.
     
  13. Red Tornado

    Red Tornado Member

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    While we're picking nits, how about 'bullet speed', since the muzzle's not really moving that fast? :evil:
    RT
     
  14. Can'thavenuthingood

    Can'thavenuthingood Member

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    Kick this around long enough and there'll be a discussional malfunction.

    Velocity indicates the speed of a projectile in flight.

    Velocity is measured in feet per second

    A direction isn't needed for velocity other than to measure between 2 points.

    Or the direction is indicated as the projectile is moving away from point of origin.

    Roger, vector Victor

    Vick
     
  15. trapperjohn

    trapperjohn Member

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    technicaly that is incorrect

    speed= distance traveled divided by the time it takes to travel it

    velocity= speed AND direction

    speed is a scalar value, it has only magnitude NOT direction

    Velocity is a vector value, it has magnitude AND direction


    that being said, that is the definition used by scientist and engineers to differentiate the two.

    for the average person velocity and speed are the same in their minds
     
  16. Andrew Rothman

    Andrew Rothman Member

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    In ENGLISH, velocity=speed.

    The question is, are we speaking English or Physicist when we talk about ballistics?

    And, jeez, this is a lame quibble. Can't even believe I'm writing this!
     
  17. M1911Owner

    M1911Owner Member

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    Yah, especially when the confusion ends up giving you specific impulse in seconds. :barf:

    More seriously, to those of us who've spent years working with vector quantities, it's self-evident that speed and velocity are completely different animals. But, that's just because physics has made a specific definition for a word that has a different meaning in the rest of the English language. To everyone else out there, "velecity" is a synonym for "speed."

    This is rather like certain groups who have decided that they don't like having the word "he" be a generic that can mean "he or she," and get all bent out of shape when people say "he" instead of "he or she."
     
  18. Obiwan

    Obiwan Member

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    What always got me was that;

    Because velocity is a vector quantity

    And because accelleration is a "change in velocity"

    That ricochet was (by definition) a form of acceleration...even if the spped remained constant.
     
  19. zahc

    zahc Member

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    Not only that, but the change it bullet speed as the bullet travels downrange is an acceleration, even though the bullet is slowing down.
     
  20. WEPS

    WEPS Member

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    velocity and speed are two diferent things. if a car was driving in a big cricle it's speed might stay the same but it's velocity would be changing. i don't remember the technical terms for it but velocity is the rate of travel in one given direction.
     
  21. RJ357

    RJ357 Member

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    You might as well include the gravitational field too, as an acceleration. Einstein showed them to be equivalent (general relativity).
     
  22. Deavis

    Deavis Member

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    Are you trying to lead us into a discussion of centripetal motion? Constant acceleration in a direction other than the velocity? Not on my watch! :neener:

    Vectors and scalars and derivatives, oh my!
     
  23. hso

    hso Moderator Staff Member

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    If you expressed your turning car's motion in polar coordinates then your velocity would be constant (jeeeeeeeeez, I'm a physics NERD )
     
  24. chevrofreak

    chevrofreak Member

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    my head just exploded
     
  25. Nippy

    Nippy Member

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    This post just went south after trapperjohn lmao
     
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