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

Homework Help: It is really sprrrrrrrrrrings

  1. Jan 19, 2004 #1
    inclined frictionless surface, end of string attached to polly (polly at top of the incline), and other end attached to a mass(m) and mass is attahed to one end of a spring, and the other end is attached to incline base
    A polly has radius (R) and moment of inertia (I), the surface is frictionless. The polly is wound clockwise to stretch the spring a distance (d) from its unstretched position and then released from rest. Find the angular speed when the spring is again unstretched or compressed.

    (E)final = (E)initial
    final[(0.5)mv^2 + (0.5)(I)w^2 + mgh + (0.5)kd^2] = initial [(0.5)mv^2 + (0.5)(I)w^2 + mgy + (0.5)kd^2]

    where (w) is omega, (y) is inital vertical distance from object to ground
    and (h) is final vertical distance from object to ground
    v(initial)=0 , w(initial)=0 , v=Rw

    from that:

    w = sqrt [(2mg(h-y) + kd^2) / (mR^2 + I)]

    is that right ??????? please i really need to know
    thnx alot for any efforts
    if u know how can i attach image file please inform me
  2. jcsd
  3. Jan 20, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    A picture would help. Use the "attach file" feature. (Edit your post; then use the feature to attach a file.)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook