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Homework Help: Torque Required To Lift

  1. Apr 19, 2009 #1
    1. The problem statement, all variables and given/known data
    Question refers to the torque required to lift the nose wheel of an aeroplane

    A retracting nose wheel assembly is raised by the application of Torque T applied to link BC through a shaft B. The wheel and Arm AO have a combined mass of 50KG with a centre of mass at G. Find the value of T necessary to lift the wheel when D is directly under B at which position angle θ is 30 degrees

    2. Relevant equations

    I have attached the figure that came with this question

    T= r x F x Sinθ where T = Torque, r = Length of the Arm, F = Magnitude of the force and θ = the angle between the two arms, but i am unsure if this is what i use to find Torque required to lift

    3. The attempt at a solution

    I have set up my own free body diagram representing this question however the part i am struggling with is setting up the equations required and getting started.
    parts i am having problems with are for the Moment Arm (D) part of the equation, is this length BC and how do i determine the Force part of the equation, I know the mass is 50kg and acceleration is Gravity = 9.8 ? any help that could point me in the right direction would be greatly appreciated

    Attached Files:

    Last edited: Apr 19, 2009
  2. jcsd
  3. Apr 19, 2009 #2
    Here is my attempt so far

    F = 50 x 9.8
    = 490 N

    T = 500mm x 490 x sin(30)
    T = 122.500

    I have no idea to tell if this is on ther right track or not
  4. Apr 19, 2009 #3


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    Staff Emeritus
    Science Advisor

    One has to determine the force applied by arm CD acting at D, which lifts G through moment arm AG.

    The force at D applies an opposite force at C on moment arm BC.

    The torque at B must balance FC acting at C of moment arm BC. When D is directly under B, BC and CD are the two legs of an isoceles triangle with base BD.
  5. Apr 19, 2009 #4
    Ok so would the Force acting at C Be the Weight of the wheel plus gravity acting to pull CD down? in this case 490 N? therefore the torque must be able to balance 490 N of opposite Force? I am still unsure how to determine the force required by Arm CD acting at D to lift G, and once i determine this Force how to translate it to Torque.
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