Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Linear and Rotational Motion Question (really struggling)

  1. Apr 28, 2010 #1
    Linear and Rotational Motion

    A load of mass 60kg is hoisted vertically by means of a light rope running over a pulley and is accelerated from 3 to 6m/s while traveling through a distance of 6 meter. If the resistance due to friction is 50N determine

    A) The pulling force in the rope
    B) The work done
    C) Average power required to accelerate this load

    So far all i have is
    Do i need to include my 50N friction resistance?

    i have F=60(9.81-6)= 228.6N

    For my work done i have
    Work done=ForcexDistance?

    Which i work out to be W.D.=(228.6+50)x6=1671.6W

    For average power i have
    Average power=W/t
    and intera torque =Ia
    However i dont know whaere to substitute in the values

    Im really stuuggling with this question and its importan for me to get correct if i want to progress onto the next course. Any hints will be much appreciated.
  2. jcsd
  3. Apr 28, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF

    Hi Dan_fitz91HNC! Welcome to PF :smile:
    (where did the 6 come from? :confused:)

    Sorry, but you need to be more systematic. :redface:

    First, find the acceleration, using one of the standard constant acceleration formulas.

    Then you can use F = ma (and yes, you have to include all the forces in F). :wink:

    What do you get? :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook