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

Pulling on a cylinder and energy lost to friction

  1. Oct 31, 2006 #1
    A spool of thin wire (with inner radius r = 0.50 m, outer radius R = 0.65 m, and moment of inertia Icm = 1.06 kg*m2 pivots on a shaft. The wire is pulled down by a mass M = 1.35 kg. After falling a distance D = 0.54 m, starting from rest, the mass has a speed of v = 70.200 cm/s. Calculate the energy lost to friction during that time.
    Not sure where even to begin!! :confused:
  2. jcsd
  3. Nov 1, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Welcome to PF !

    Please read our guidelines concerning homework which you agreed upon:
    - post them in the appropriate homework section (in this case: intro physics; I'll move the thread after this post)

    - show some work before others are even allowed to help you.

    This policy is not to make life hard for you, on the contrary...

    However, I'm going to give you a hint in approaching the problem:
    if you know the energy at the beginning, and at the end, then the difference might have something to do with friction (because if there weren't any, both would be the same).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook