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Falling Bullet

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  • 24-01-2011 4:11pm
    #1
    Tar.Aldarion
    Moderators, Science, Health & Environment Moderators, Social & Fun Moderators, Society & Culture Moderators Posts: 60,082 Mod ✭✭✭✭


    If on one hand you shot a gun along a horizontal path across the ground and in the other dropped a bullet out of your hand, both would hit the ground at the same time.


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    #2
    c-note
    Registered Users Posts: 434 ✭✭c-note


    Tar.Aldarion wrote: »
    If on one hand you shot a gun along a horizontal path across the ground and in the other dropped a bullet out of your hand, both would hit the ground at the same time.

    (in a vaccume, with no curvature to the earth).(sry i'm being pedantic!:p)


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    #3
    Tar.Aldarion
    Moderators, Science, Health & Environment Moderators, Social & Fun Moderators, Society & Culture Moderators Posts: 60,082 Mod ✭✭✭✭Tar.Aldarion


    c-note wrote: »
    (in a vaccume, with no curvature to the earth).(sry i'm being pedantic!:p)

    there is no room for science in here! :P
    would only be a small difference in our imperfect conditions, the fired bullet taking slightly longer to land.
    When i saw the test done before the difference was so slight the human eye could not tell the difference. Think it's pretty cool anyway!


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    #4
    c-note
    Registered Users Posts: 434 ✭✭c-note


    yeah i heard it stated a different way, as a trick question

    You have a laser sight on you rifle which fires bullets at 500m/s
    its pointed at the chest of a monkey, in a triee, 500 meters away

    The instant you fire, with the laser pointer aimed at the monkeys chest, the monkey falls from the tree.

    roughly where will the bullet impact the monkey, if at all.
    it is .4m from the point at which the laser was pointed to beyond the top of the monkeys head.

    (the answer of couse is that it wil hit the monkey at the precise spot at which the laser was pointed)


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    #5
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,725 Mod ✭✭✭✭Capt'n Midnight


    c-note wrote: »
    yeah i heard it stated a different way, as a trick question

    You have a laser sight on you rifle which fires bullets at 500m/s
    its pointed at the chest of a monkey, in a triee, 500 meters away

    The instant you fire, with the laser pointer aimed at the monkeys chest, the monkey falls from the tree.

    roughly where will the bullet impact the monkey, if at all.
    it is .4m from the point at which the laser was pointed to beyond the top of the monkeys head.

    (the answer of couse is that it wil hit the monkey at the precise spot at which the laser was pointed)
    the rifle must be horizontal

    and of course the distance to the ground is less than 4.9 meters


    ( I've split the discussion from the facts thread. )


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    #6
    King Mob
    Registered Users Posts: 25,226 ✭✭✭✭King Mob


    Tar.Aldarion wrote: »
    If on one hand you shot a gun along a horizontal path across the ground and in the other dropped a bullet out of your hand, both would hit the ground at the same time.
    Myhtbusters to the rescue!

    https://www.youtube.com/watch?v=D9wQVIEdKh8


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    #7
    Tar.Aldarion
    Moderators, Science, Health & Environment Moderators, Social & Fun Moderators, Society & Culture Moderators Posts: 60,082 Mod ✭✭✭✭Tar.Aldarion


    apparently i have my own thread now! :p


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    #8
    5uspect
    Moderators, Arts Moderators Posts: 10,515 Mod ✭✭✭✭5uspect


    You have your own forum.


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    #9
    Tar.Aldarion
    Moderators, Science, Health & Environment Moderators, Social & Fun Moderators, Society & Culture Moderators Posts: 60,082 Mod ✭✭✭✭Tar.Aldarion


    yes but but i want moar. Somebody made this thread from a post i made in another thread


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    #10
    Mr Marri
    Closed Accounts Posts: 266 ✭✭Mr Marri


    c-note wrote: »
    (in a vaccume, with no curvature to the earth).(sry i'm being pedantic!:p)

    Depends on the speed of the bullet, if it was fast enough it could take hours to hit the ground.

    Also the bullet would have to be heavier than air or it would float away :pac:


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    #11
    Mr Marri
    Closed Accounts Posts: 266 ✭✭Mr Marri


    Mr Marri wrote: »
    Depends on the speed of the bullet, if it was fast enough it could take hours to hit the ground.

    Also the bullet would have to be heavier than air or it would float away :pac:

    Oh and if there was cross wind the bullet would rise (I think) depending on the speed of rotation :pac:


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    #12
    5uspect
    Moderators, Arts Moderators Posts: 10,515 Mod ✭✭✭✭5uspect


    It would also experience lift due to the shockwaves at the leading edge. The pressure difference caused by any change in orientation of the round relative to it's flight path would affect the trajectory.

    So as c-note says, yes it'll work in a vacuum.


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    #13
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,725 Mod ✭✭✭✭Capt'n Midnight


    Mr Marri wrote: »
    Depends on the speed of the bullet, if it was fast enough it could take hours to hit the ground.
    if we are neglecting air resistance then if the bullet could stay up more than 88 minutes it would never hit the ground. Because it would either be in orbit or have achieved escape velocity.


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    #14
    djpbarry
    Registered Users Posts: 13,104 ✭✭✭✭djpbarry


    c-note wrote: »
    yeah i heard it stated a different way, as a trick question

    You have a laser sight on you rifle which fires bullets at 500m/s
    its pointed at the chest of a monkey, in a triee, 500 meters away

    The instant you fire, with the laser pointer aimed at the monkeys chest, the monkey falls from the tree.

    roughly where will the bullet impact the monkey
    In the tree.


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    #15
    Alvin T. Grey
    Closed Accounts Posts: 1,169 ✭✭✭Alvin T. Grey


    What have you got against monkeys?


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    #16
    FarmerGreen
    Registered Users Posts: 1,134 ✭✭✭FarmerGreen


    Couple of things here, The intererior ballistics of weapons are probably the most important part, the exterior i.e wind and gravity is important also.
    Thats where you come in.
    If you actually want to make a small piece of metal arrive at a place with this kit is to ..........


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    #17
    krd
    Banned (with Prison Access) Posts: 3,455 ✭✭✭krd


    c-note wrote: »
    yeah i heard it stated a different way, as a trick question

    You have a laser sight on you rifle which fires bullets at 500m/s
    its pointed at the chest of a monkey, in a triee, 500 meters away

    The instant you fire, with the laser pointer aimed at the monkeys chest, the monkey falls from the tree.

    roughly where will the bullet impact the monkey, if at all.
    it is .4m from the point at which the laser was pointed to beyond the top of the monkeys head.

    (the answer of couse is that it wil hit the monkey at the precise spot at which the laser was pointed)

    If the laser sight is calibrated for a target at 500 meters. It will hit the monkey at the precise spot the laser is targeted on.

    For rifles that let you adjust the height of the sight - for further away targets you must set your sights higher. Because the bullet starts to fall as soon as it leaves the gun.


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    #18
    thecornflake
    Registered Users Posts: 784 ✭✭✭thecornflake


    If you fire it too fast it could go into orbit, and we can't be having that now can we ?

    Also if fired fast enough it could rip a hole in the fabric of space time due to the mass increase ect meaning that the bullet would hit the ground in 1882 as opposed to when the free fall bullet hit the ground. That's a delta time of 128 years so on this very strong scientific grounds I would have to say no OP you are wrong.

    Further more, the uncertainty principal states we cannot know the exact position and momentum of either bullet, so can we be certain of when and where they hit the ground and with what energy and momentum ?

    :rolleyes: I hate when people state problems like this without thinking of the obvious flaws.


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    #19
    AlmightyCushion
    Moderators, Education Moderators, Technology & Internet Moderators Posts: 35,046 Mod ✭✭✭✭AlmightyCushion


    thecornflake wrote: »
    If you fire it too fast it could go into orbit, and we can't be having that now can we ?

    Also if fired fast enough it could rip a hole in the fabric of space time due to the mass increase ect meaning that the bullet would hit the ground in 1882 as opposed to when the free fall bullet hit the ground. That's a delta time of 128 years so on this very strong scientific grounds I would have to say no OP you are wrong.

    Further more, the uncertainty principal states we cannot know the exact position and momentum of either bullet, so can we be certain of when and where they hit the ground and with what energy and momentum ?

    :rolleyes: I hate when people state problems like this without thinking of the obvious flaws.

    Yes the obvious flaw that is the fact it could rip a hole in space time and travel backwards in time. How did that ever evade him.


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    #20
    thecornflake
    Registered Users Posts: 784 ✭✭✭thecornflake


    AlmightyCushion wrote: »
    Yes the obvious flaw that is the fact it could rip a hole in space time and travel backwards in time. How did that ever evade him.

    Well isn't it obvious ? Clearly it evaded him because the answer came before the question (a la rip in the space time continuum ). Thus what we have done here good sir with this simple thought experiment is prove that causality is no longer !

    I have derived an equation for said fact if you would care to take a look:

    e^(x + space-time fabric rip length) X monkey velocity = 1 / 0

    i.e. infinity,

    lets examine this interesting result for a minute. Infinity. Infinite, that's right, the probability density for the projectile (aka the bullet) hitting the monkeys grandfather in 1882 is infinite.

    your move Almighty Cushion, your move . . . . .


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    #21
    ray giraffe
    Registered Users Posts: 338 ✭✭ray giraffe


    Capt'n Midnight wrote: »
    the rifle must be horizontal

    Don't think rifle needs to be horizontal!


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    #22
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,725 Mod ✭✭✭✭Capt'n Midnight


    ray giraffe wrote: »
    Don't think rifle needs to be horizontal!
    Have a look at the original question again ;)


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    #23
    Allosaur
    Registered Users Posts: 128 ✭✭Allosaur


    ray giraffe wrote: »
    Don't think rifle needs to be horizontal!
    Yes it does, if not you have a parabolic tragectory, or effectivly a "loft". It increases the range and hence the time the bullet is in flight.


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    #24
    TheChizler
    Registered Users Posts: 9,405 ✭✭✭TheChizler


    Reminds me of a video we were shown in 1st year Physics in UCC.


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