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    Quesiton:

    ABCD is a uniform square lamina of side 4m and mass 8kg. It is hinged at A so that it is free to move in a vertical plane. It is maintained in eqilibrium with B vertically below A by a horizontal force acing at C and a verticle force acting at D, each of magnitude F newtons.

    Find the value of F?

    Can anybody show me how they got an answer of 19.6N.

    Cheers :tsr:
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    (Original post by Revenged)
    Quesiton:

    ABCD is a uniform square lamina of side 4m and mass 8kg. It is hinged at A so that it is free to move in a vertical plane. It is maintained in eqilibrium with B vertically below A by a horizontal force acing at C and a verticle force acting at D, each of magnitude F newtons.

    Find the value of F?

    Can anybody show me how they got an answer of 19.6N.

    Cheers :tsr:

    moments C.W. = moments A.C.W.
    8g . 2 = F.4 + F.4
    16g = 8F
    F = 2g
    F = 9.8 x 2
    F = 19.6 N
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    Thanks, i never knew that rule
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    from what point are you taking the moments about?
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    A, as it's hinged from A
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    wouldnt it be then root(4^2 + 2^2) x 8g ? as thats the distance of A from 8g ?
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    moments = F . distance perpendicular
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    oh ok, i never knew that rule either! thanks
 
 
 
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