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Wonder about instant Acceleration

  1. Nov 2, 2009 #1
    About jump from speed 0 to 100 without passing 1 - 99.

    Can Objects with mass do someting like that?

    or it's already can but I don't know?

    ........................................

    Example bullet speed is 100, When we shooting bullet, is bullet move to its speed by instant? or still climb form 1 to 100 even in millisecond?

    .............................

    PS. English is not my native language, please forgive me if I'm wrong in gramma.
     
  2. jcsd
  3. Nov 2, 2009 #2

    Danger

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    Welcome to PF, Chitose.
    The only way that something could experience an instantaneous acceleration would be if its mass was decreased to zero. (Isaac Asimov actually pulled off a pretty cool murder that way in one of his short stories.) That is not, however, physically possible. Bullets undergo tremendous g-loads, but all are different. A mass-driver (electromagnetic catapult) is capable of about 130 g's as of my last information input. Nothing with mass goes from rest to speed without an acceleration period.
    By the bye... you communicate quite well in English. It's obvious that you aren't fluent in it, but you certainly didn't leave any doubt as to your question. I've encountered posters (and people in real life) who have English as a first and only language, who are far less understandable than you are. :smile:
     
  4. Nov 3, 2009 #3

    A.T.

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    The bullet accelerates in the barrel. The longer the barrel, the faster the bullet. Longest barrels ever build:
    http://en.wikipedia.org/wiki/V-3_cannon
     
  5. Nov 3, 2009 #4
    Also depends on resistant factors such as wind and structure of object, even the temperature and moisture in the air can play a part, and this follows into the medium in which the accelerated object is pasting through. Even the speed that light travels can vary given it's apposing environmental elements.
     
  6. Nov 3, 2009 #5

    Danger

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    A couple of comments regarding the last 2 posts. The length of the barrel is only productive until the point where the internal pressure drops to atmospheric. That pretty much never happens in real life, but it is something to consider.
    As to the second post, it must be noted that the speed of a photon is always c. The propagation speed of the light signal is altered by the atomic structure of the medium. There are a few very educational threads regarding that subject hereabouts. A forums search will pull them up quickly.
     
  7. Nov 3, 2009 #6
    High acceleration means strong force. Usually any force is applied on body surface, not to all particles of the body. Than means the body gets strongly deformed and destroyed with that force! Think of a bullet hitting an infinitely stiff wall. The bullet gets smashed. The same happens if you want to give an instant velocity to a resting bullet by hitting it with a stiff wall.
     
    Last edited: Nov 3, 2009
  8. Nov 3, 2009 #7

    Danger

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    You have a strange approach to things, Short Bob... and I love the way that you think. :biggrin:
    Incidentally, I pretty much couldn't understand more than a couple of words in your linked blog, but it looked cool.
     
  9. Nov 3, 2009 #8
    As a matter of fact, I am not a short Bob but rather a fat one. My full name is Vladimir Leonidovich Kalitvianski, - hard to remember and pronounce, that's why I call myself Bob_for_short.
     
  10. Nov 3, 2009 #9

    Danger

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    By your avatar, you don't seem to be much overweight (at least by North American standards). Pretty much everyone is heavy to me, though. I'm currently the fattest that I've ever been, due to a massive intake of beer and beef. I have ballooned to 132 lbs. in the past couple of years. Damn!... I'm a blimp!
    Now shut up and go do something rude to your wife or girlfriend or both. :tongue:
     
  11. Nov 3, 2009 #10
    I see...
    So as long as object still have mass, no matter how strong force pushing or pulling, It can't go to speed without acceleration period.

    Thank you.
    .........................................
    I still have lot more question about physic and stuff, glad to find this forum.
     
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