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AS Physics - Help with moments question Watch

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    Hey guys, hoping you can help me with this question on moments. I'm struggling to understand the whole principle right now.

    Link to the paper: http://www.ocr.org.uk/images/58048-q...-mechanics.pdf

    Would post the Q here, but contains diagrams.

    Anyway, it's question (6)(a)(ii).

    (6)(c)(ii) also gave me a bit of trouble, but I think I figured it out with a little help from the mark scheme.

    Thanks for any help
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    What exactly have you done for both parts?
    Or are you just generally stuck?
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    Moment = force x perpendicular distance
    Anticlockwise moments are positive, clockwise ones are negative.
    Total moment = Sum of anticlockwise and clockwise moments.

    Also: anticlockwise 4N force, perpendicular distance is x
    clockwise 4N force, perpendicular distance is (x + 3.0cm)
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    Okay thanks guys Probably should have put a bit of work down.

    1)

    So, the clockwise moment would be: 4.0 x (0.03 + x)
    And the anticlockwise moment would be: 4x

    Right?

    So do we add these together to find the total moment?
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    Oh wait, if you meant clockwise moments are positive, then I think I've got it.

    Clockwise = 4 x (0.03 + x) = 0.12 + 4x

    Therefore, total moment = 0.12 + 4x - 4x which equals 0.12.

    Significance being it is the same value as the torque!
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    (Original post by NoNamedUser)
    Oh wait, if you meant clockwise moments are positive, then I think I've got it.

    Clockwise = 4 x (0.03 + x) = 0.12 + 4x

    Therefore, total moment = 0.12 + 4x - 4x which equals 0.12.

    Significance being it is the same value as the torque!
    correct
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    the moment of a couple is equal to the force times the perpendicular distance

    so the solution is
    Moment=Fd
    = 4x(3x10^-2)
    = 0.12Nm
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    (Original post by NoNamedUser)
    Oh wait, if you meant clockwise moments are positive, then I think I've got it.

    Clockwise = 4 x (0.03 + x) = 0.12 + 4x

    Therefore, total moment = 0.12 + 4x - 4x which equals 0.12.

    Significance being it is the same value as the torque!
    Indeed correct.
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    Thanks guys
 
 
 
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