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  1. Sep 26th, 2001, 12:34 PM #1
    DavidHooper
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    A new thread!...

    No threads for quite a while - here's one to keep us ticking over...

    Where is the centre of gravity of a hemisphere?

    Your answers, clues, thoughts and questions?...
    There are 10 types of people in the world - those that understand binary, and those that don't.
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  2. Sep 26th, 2001, 01:14 PM #2
    chrisf
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    For a solid hemesphere its 3 * r / 8 from the center of the base.
    For a hemespherical shell its r / 2 from the center of the base.
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  3. Sep 26th, 2001, 04:53 PM #3
    nishantp
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    well this thread ended pretty fast.
    You just proved that sig advertisements work.
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  4. Sep 27th, 2001, 01:40 PM #4
    thinktank
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    A hemisphere of malleable material is flattened in to a thin sheet after making a cut along it's surface (pole to pole).
    Where is it's C.G ?
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  6. Sep 27th, 2001, 02:54 PM #5
    DavidHooper
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    did u work that out chrisf or quote it?? it was pretty fast!

    i don't understand ure description thinktank - aren't you describing a square??
    There are 10 types of people in the world - those that understand binary, and those that don't.
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  7. Sep 27th, 2001, 06:33 PM #6
    chrisjk
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    Does the maths forum increment post count...?
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  8. Sep 27th, 2001, 06:33 PM #7
    chrisjk
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    Aparently yes...interesting. I'll stop posting crap now...
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  9. Sep 28th, 2001, 04:29 AM #8
    chrisf
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    Originally posted by DavidHooper
    did u work that out chrisf or quote it?? it was pretty fast!
    I've done these problems before, I just dug out my old notes.

    ThinkTank, if you make your hemisphere from a thin sheet you will have a hemisperical shell C. of G. = r / 2 from the center of the base.
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  11. Sep 28th, 2001, 04:12 PM #9
    DavidHooper
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    Oh ok...

    Oh ok. it can be done by taking strips of sqrt(1-x^2), finding area and relative mass then letting dx -> 0 and finding the solution by taking moments around the origin. I expect this is the way you did it all those years ago!

    All the forums increment the same count - megatron has the highest count...
    There are 10 types of people in the world - those that understand binary, and those that don't.
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