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Homework Help: Inclined plane moment of inertia

  1. May 1, 2010 #1
    1. The problem statement, all variables and given/known data

    A block with mass m = 5.00 kg slides down a surface inclined 36.9 to the horizontal. The coefficient of kinetic friction is 0.25. A string attached to the block is wrapped around a flywheel has mass 25.0 kg and moment of inertia 0.500 kgm2 with respect to the axis of rotation. The string pulls without slipping at a perpendicular distance of 0.200 m from that axis.
    a) What is the acceleration of the block down the plane
    b) What is the tension in the string
    2. Relevant equations



    3. The attempt at a solution
    Ok ive been having a lot of trouble with things involving moments of inertia. ive found the friction that opposes the motion to be 9.81N. but how do i calculate the opposing force that the flywheel provides? any help is appreciated, as always..
     
  2. jcsd
  3. May 1, 2010 #2

    ehild

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    Could you please show a picture?

    ehild
     
  4. May 1, 2010 #3

    ehild

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    Could you please show a picture?

    ehild
     
  5. May 1, 2010 #4
    How do you show a picture in a reply?? ive attached it as a word doc.
     

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  6. May 1, 2010 #5
    Use the relationship [tex]\alpha[/tex]=a/r and solve the torque equation for a.
     
  7. May 1, 2010 #6
    you mean mg-T=ma??
     
  8. May 1, 2010 #7
    First sum up all of the forces for the block.

    [tex]\Sigma[/tex]Fx=sin[tex]\theta[/tex]*Fg-Ff-T=ma

    Then get the pulley

    [tex]\Sigma\tau[/tex]=I*[tex]\alpha[/tex]
     
  9. May 1, 2010 #8
    Ok ill do that and report back with my answer, thanks.
     
  10. May 1, 2010 #9
    Hey is the answer a=1.123m/s^2 and T=14N thanks
     
  11. May 2, 2010 #10

    ehild

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    Yes, it is!

    ehild
     
  12. May 3, 2010 #11
    Hey Pat,

    Could you describe what you've done to come up with those answers? I couldn't follow.

    Cheers
     
  13. May 3, 2010 #12
    why do you want to follow, more cqu peoples???
     
    Last edited: May 3, 2010
  14. May 3, 2010 #13
    which part?
     
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