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

Rotation and Linear Motion BonuS Help

  1. Mar 4, 2007 #1
    1. The problem statement, all variables and given/known data

    A system consists off two small disks of masses m and 2m that are on a plane. The length that connects the two mass is of negligible mass is is 3L long. The rod is free to rotate on a vertical axis P and the mass 2m lies L away from P and the mass m lies 2L away from P. The two disks rest on a horizontal surface and the coefficient of friction is U. At time t = 0, the rod has an initial counterclockwise angular velocity of Wi about P. The system is gradually brought to rest by friction. develop expressions for the following in terms of u, m, L, g, and Wi.
    a) the frictional torque acting on the system about axis P
    b) the time T at which the system will come to rest.

    2. Relevant equations

    Wf= Wi + (alpha)t
    0 = Wi + (alpha)t

    3. The attempt at a solution

    Wi - friction = I (alpha)

    what do i use for Inertia?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?