1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Yo-Yo problem

  1. Dec 7, 2013 #1
    1. The problem statement, all variables and given/known data
    A yoyo of mass m=2 kg and moment of inertia ICM=0.0625 kg m2 consists of two solid disks of radius R=0.25 m, connected by a central spindle of radius r=0.1875 m and negligible mass. A light string is coiled around the central spindle. The yoyo is placed upright on a flat rough surface and the string is pulled with a horizontal force F=28 N, and the yoyo rolls without slipping.
    The force is applied at the top of the spindle; so above the center of mass.

    Find the acceleration of the yo-yo.
    Find the frictional force
    2. Relevant equations
    F-fr=ma
    Tq=I*alpha


    3. The attempt at a solution

    I started taking moments about the centre of mass, which came to R*fr - r*F = Torque
    Then equated this with the Inertia and alpha.
    R*fr - r*F = I*alpha
    Then changed alpha to a/R.
    So ended up with a = ((R*fr - r*F)*R)/I
    I then use the F-fr=ma equation to solve for both fr and a.
    The answers i get are incorrect.
     
  2. jcsd
  3. Dec 8, 2013 #2

    ehild

    User Avatar
    Homework Helper
    Gold Member

    Are you sure the torque of the friction acts against the torque of the applied force???




    ehild
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Yo-Yo problem
  1. Yo Yo Problem (Replies: 1)

  2. YO-YO Problem (Replies: 1)

  3. Yo-Yo problem (Replies: 0)

  4. Yo-Yo problem (Replies: 1)

Loading...