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Simple physics question

  1. Jul 2, 2006 #1
    why does the bombs and the plane form a "straight line" in the y-axis? the plane is accelerating away in the x-axis at a certain speed, so my thinking is that the bombs that were released should be some distances from the plane
     

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  2. jcsd
  3. Jul 2, 2006 #2

    Doc Al

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    Why do you assume the plane is accelerating?
     
  4. Jul 2, 2006 #3

    Danger

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    Ukitake, you have to be careful with your terminology around here. Stop and think about the motion of the aeroplane and its contents. Is there acceleration? If so, what vector?
     
  5. Jul 2, 2006 #4
    what is most likely is that the plane is maintaining a constand speed and one would presume that as the bombs are dropped and so no longer benifit from the engine which is requireered to overcome primarily air resistence and keep the plane at a constant speed, the bombs would be expected to descelerate due to air risistence (so if you took the bomb as your point of reference you *could* say that in relation to the first bomb the plane was accelerating, although this would be a funny way at looking at it). so given all this you would presume that the first bomb dropped would descelerate first and so at the moment the second bomb is dropped the first bomb has decelerated and so is someway behind the plane and second bomb, so bomb after bomb you would expect that the bombs trail off behind the plane. But in answere to you question it is most likely that simply the bombs are dropped in very quick succesion and this combined with their high density and relitivly low air resistence meens that they will decelerate slowly and so that first period of desceleration between the time of the first bomb being droppped and the last bomb being dropped is insuficient for the bombs to trail out. otherwise there is the possability that theses are very smart bombs and employ a propulsion system combined with a speed controller that maintains the bomps at a constand forward velocity.(unlikly tho)

    hope this makes some sense
     
  6. Jul 5, 2006 #5
    hmmm....hard to tell if there is acceleration but i assume there isnt any acceleration
     
  7. Jul 5, 2006 #6
    on 2nd thoughts i think there is no acceleration which is why the bombs fall in 1 line

    i rem an example about a car moving at constant speed and someone fires a bullet upwards and ignoring all other factors where will the bullet land?

    and the question gave 3 choices 1) bullet falls ahead of the car 2) bullet falls behind the car 3) bullet falls back into the barrel

    bullet will fall back into the barrel becoz the bullet is travelling at the same speed as the car in the x-component and all other factors are ignored
     
  8. Jul 5, 2006 #7

    Doc Al

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    Sounds good to me.
     
  9. Jul 5, 2006 #8

    Hootenanny

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    Makes sense :smile:
     
  10. Jul 5, 2006 #9

    Danger

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    You got it, bud. :smile:
     
  11. Jul 5, 2006 #10

    tony873004

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    The bombs in that picture are trailing a tad bit, with the lower ones trailing more. I'd imagine this is for the reasons josh444 brough up.
     
  12. Jul 5, 2006 #11

    Danger

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    Good point, Tony. That effect, however, is a direct result of air resistance acting upon the bombs which have no forward propulsion mechanism. In vacuum, they would drop directly.
     
  13. Jul 8, 2006 #12
    in real life the bullet will not fall back into the gun barrel due to many factors, which factor is the most significant in causing deviation in the bullet trajectory?
     
  14. Jul 8, 2006 #13

    Danger

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    Since all of the factors could be at least theoretically eliminated, I don't know that it would be proper to consider a difference in their importance levels. The easiest to eliminate might actually be the inherent accuracy of the gun itself. If the barrel/chamber is micro-machined, properly crowned & accoustically tuned to the ammo, it might be possible to get the bullet to come straight back down in the absence of the other factors. The bullet would also have to be micro-machined. In that light, you could perhaps consider that to be the least important one.
     
    Last edited: Jul 9, 2006
  15. Jul 8, 2006 #14

    tony873004

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    I imagine wind would be the biggest factor. Ignoring that, you'd have to do it at the North or South pole. The Earth is spinning and that would affect the path of the bullet. The bullet would have the linear momentum of the Earth's surface when it left the barrel, but Earth's surface is not moving linearly, so after a short while, the gun and the bullet would no longer be aligned. Not by much though, but probably enough to make it miss the barrel of the gun. You could always account for this and move the gun a precisely calculated distance so it could catch the bullet. It would only be a few millimeters.
     
  16. Jul 9, 2006 #15
    sweet, thanks to all who took time out to ans my question :)
     
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