1. Limited time only! Sign up for a free 30min personal 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!

Rotational motion

  1. Dec 11, 2011 #1
    A thin spherical shell lying on a rough horizontal floor is hit by a cue in such a way that the line of action of force passes through the centre.so there is no torque and it moves with a linear velocity V and no angular velocity.the linear velo is to be founded when the shell starts purely rolling.
    now the question goes whether the principal of conservation of angular momentum is valid here.i don't think so because an external torque due to friction will be acting on it.
    [. The shell will move with a velocity nearly equal to v due to this motion a frictional force well act in the
    background direction, for which after some time the shell attains a pure rolling. If we
    consider moment about A(the point of contact with the floor), then it will be zero. Therefore, Net angular momentum
    about A before pure rolling = net angular momentum after pure rolling.]
    This is what my textbook says but it makes me wonder.
     
  2. jcsd
  3. Dec 11, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Note that they are taking moments about a point of contact with the floor. What's the torque about that point due to friction?

    The angular momentum about the center of mass is certainly not conserved.
     
  4. Dec 12, 2011 #3
    so could u please give me some idea how should i try to solve it?
     
  5. Dec 13, 2011 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Well, how about using conservation of angular momentum, as suggested by your text?

    Set the initial angular momentum (when the sphere is just translating at speed V) equal to the final angular momentum (when it's rolling without slipping).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Rotational motion
  1. Rotational Motion (Replies: 6)

  2. Rotation motion (Replies: 1)

  3. Rotational motion. (Replies: 5)

Loading...