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Homework Help: Rotational Work

  1. Sep 21, 2015 #1


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    A) Questions, Equations & Attempts on answering

    1) If I'm correct, for linear cases, Work= Fs,

    F= Constant Force
    s= Displacement

    where Work can= negative if displacement ends up in the opposite direction, am I right?

    2) Rotational Work= Fs

    = Frφ

    = τφ,

    F= Constant Force
    s= Displacement
    r= Displacement for rotational work
    φ= Resultant Angle
    τ= Torque,

    and the case being considered,

    220px-Work_on_the_lever_arm.jpg .

    Just confirming, say, at point F, this line, r's been spun -360°x10 times, if F increases, does that mean Rotational Work increases?

    3) For 2), as r's been spun 360°x10 times counter clockwise, it won't be a negative work value would it?
  2. jcsd
  3. Sep 21, 2015 #2

    Doc Al

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    Staff: Mentor

    If the force points in the direction of the displacement, then the work done will be positive; if it points opposite to the displacement, then negative.
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