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

Rolling and sliding sphere on flat surface

  1. Sep 4, 2011 #1
    1. The problem statement, all variables and given/known data

    In a laboratory experiment two spherical balls are launched on a °at surface. Both are
    uniform spheres of radius R and mass m. They are both given the same amount of
    initial kinetic energy K0. However:
    -ball A rolls without slipping
    -ball B slides without rotating
    What is the ratio Vb/Va?

    2. Relevant equations
    Moment of inertia of solid sphere= 2/5 (mr^2)

    3. The attempt at a solution
    for the rotating, I did

    KErolling=1/2 mv^2 = 1/2 Iw^2 => KEo = 7/10 mv^2

    then for the slipping, I'm having a bit of problem. I am not sure if i have to include the friction force or not. Without friction, it'd be F=ma, then KEo=ma, I'm not sure if i can substitute KEo as F or not..

  2. jcsd
  3. Sep 4, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Since B slides without rotating, the friction force must be zero.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook