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Homework Help: Lifting a canister with a pulley

  1. Oct 11, 2006 #1
    In the figure, a cord runs around two massless, frictionless pulleys; a canister with mass m = 25 kg hangs from one pulley; and you exert a force F on the free end of the cord. What must be the magnitude of F if you are to lift the canister at a constant speed?

    Here i know that the answer is mg*d. So 25*9.81*0.066m but i am not getting the answer. as i have in the book. in the previous question was To lift the canister by 3.3 cm i had to lift it by 6.6 cm so i dont what i am doing that i s wrong. Thanks for the help
     
  2. jcsd
  3. Oct 11, 2006 #2

    berkeman

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    Staff: Mentor

    There is no figure associated with your post, but from the last thing you said, it sounds like the pulley arrangement gives you a 2:1 force advantage. Did you take that into account in your calculation for the first question?
     
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