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Thread: tell me about free fall

  1. #1 tell me about free fall 
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    A question from gravity.If I drop two things from a building , say gold and aluminium of same shape and size , which will fall first? or they will fall at the same time?and if I repeat the same activity in vaccum , what will happen?What matters in free fall?


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  3. #2 Re: tell me about free fall 
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    Quote Originally Posted by sciman
    A question from gravity.If I drop two things from a building , say gold and aluminium of same shape and size , which will fall first? or they will fall at the same time?and if I repeat the same activity in vaccum , what will happen?What matters in free fall?
    They will land at the same time, every time. Only if one imparts more air resistance will there be a difference.


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  4. #3 when? 
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    when one will impart more air resistance?you did not tell me what will happen in vaccum?
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  5. #4 Re: when? 
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    Quote Originally Posted by sciman
    when one will impart more air resistance?
    When one is slowed down by the air more than the other because of its shape


    you did not tell me what will happen in vacuum?[/quote]

    anythings will land at the same time without exception. The pure acceleration due to gravity( 9.8 m s ^-2) is all that applies.
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  6. #5 paper and gold 
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    what if we take paper and gold of same shape and size?will they fall at the same time?
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  7. #6 Re: paper and gold 
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    Quote Originally Posted by sciman
    what if we take paper and gold of same shape and size?will they fall at the same time?
    If they have the same air resistance , yes.

    The mass of the objects doesn't matter.


    You ever heard of the famous leaning tower of piza experiment?
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  8. #7 Re: paper and gold 
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    Quote Originally Posted by GhostofMaxwell
    Quote Originally Posted by sciman
    what if we take paper and gold of same shape and size?will they fall at the same time?
    If they have the same air resistance , yes.

    The mass of the objects doesn't matter.


    You ever heard of the famous leaning tower of piza experiment?
    That's not exactly right. With equal air resitance the heavier object falls faster. Terminal velocity will be reached when the weight = air resistance.
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  9. #8 Re: paper and gold 
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    Quote Originally Posted by Harold14370
    Quote Originally Posted by GhostofMaxwell
    Quote Originally Posted by sciman
    what if we take paper and gold of same shape and size?will they fall at the same time?
    If they have the same air resistance , yes.

    The mass of the objects doesn't matter.


    You ever heard of the famous leaning tower of piza experiment?
    That's not exactly right. With equal air resitance the heavier object falls faster. Terminal velocity will be reached when the weight = air resistance.
    Yeah but I was talking of small distance where terminal velocity isn't reached for either object.
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  10. #9 Re: tell me about free fall 
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    Quote Originally Posted by sciman
    A question from gravity.If I drop two things from a building , say gold and aluminium of same shape and size , which will fall first? or they will fall at the same time?and if I repeat the same activity in vaccum , what will happen?What matters in free fall?
    Gravity self-aware?

    Geeeees God!

    Should gold "rise" first..........in theory?

    Or is, was, should be, the aim to do something constructive with this planet, be from above..........are the riches placed for those who make the effort to communicate with this ground zero planet????

    .....this is "philosophy", Yaaaaaaaa?

    When science fails, surely some other explanation enterains even the most inn-inn-inn-stituted student...........to some point of being a "star".
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  11. #10 Re: paper and gold 
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    Quote Originally Posted by GhostofMaxwell
    Yeah but I was talking of small distance where terminal velocity isn't reached for either object.
    Still not correct. A bucket of lead will fall faster than a bucket of feathers, whether or not either one reaches terminal velocity.

    The net downward accelerating force is equal to the weight mg minus the air resistance. For a given speed the air resistance of similar shapes is the same.

    Let X = the air drag, the same for both masses. Then acceleration is (mg-X)/m = g-X/m which increases with increasing m.
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  12. #11  
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    wELL YOU'VE OBVIOUSLY STUDIED air resistance in depth, Harold. I stand corrected.
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  13. #12  
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    The better way to test it is to roll them down a hill, but yes, they will allways land at the same time, if they are of an identicle shape, but different mass.
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  14. #13  
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    Quote Originally Posted by ten_ben
    The better way to test it is to roll them down a hill, but yes, they will allways land at the same time, if they are of an identicle shape, but different mass.
    This is true only in a vacuum.
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  15. #14  
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    Quote Originally Posted by Harold14370
    Quote Originally Posted by ten_ben
    The better way to test it is to roll them down a hill, but yes, they will always land at the same time, if they are of an identical shape, but different mass.
    This is true only in a vacuum.
    I am certain that if they are of the exact same shape, they will fall at the same rate, regardless of mass and vacuums.

    Heavy item - more mass so more gravitational pull, but more inertia.
    Lighter item - less gravitational pull, but less inertia.
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  16. #15  
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    Quote Originally Posted by ten_ben
    Quote Originally Posted by Harold14370
    Quote Originally Posted by ten_ben
    The better way to test it is to roll them down a hill, but yes, they will always land at the same time, if they are of an identical shape, but different mass.
    This is true only in a vacuum.
    I am certain that if they are of the exact same shape, they will fall at the same rate, regardless of mass and vacuums.

    Heavy item - more mass so more gravitational pull, but more inertia.
    Lighter item - less gravitational pull, but less inertia.
    But your explanation does not account for the air resistance.
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  17. #16  
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    Quote Originally Posted by Harold14370
    Quote Originally Posted by ten_ben
    Quote Originally Posted by Harold14370
    Quote Originally Posted by ten_ben
    The better way to test it is to roll them down a hill, but yes, they will always land at the same time, if they are of an identical shape, but different mass.
    This is true only in a vacuum.
    I am certain that if they are of the exact same shape, they will fall at the same rate, regardless of mass and vacuums.

    Heavy item - more mass so more gravitational pull, but more inertia.
    Lighter item - less gravitational pull, but less inertia.
    But your explanation does not account for the air resistance.
    Yes but if they are exactly the same shape, then surely air resistance will be the same?
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  18. #17  
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    I think the point that Harold has made, is that although the mass of everyday objects is negligible compared to the earth mass . An object with a higher weight (a stronger force) will act against air more strongly than an object with less weight, even though they may have exactly the same shape.
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