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!

Homework Help: Why does friction create rolling?

  1. Aug 10, 2008 #1
    Consider a round object given a push at the middle. The push generates linear velocity, and If there wasn't any friction, the object would start sliding; but the friction in the contact point with the ground causes the object to start rolling.

    Intuitively I can explain it: the friction causes the linear speed of the contact point to diminish, and since the other parts of the object still move in the same velocity, rolling is created.

    But could somebody provide me with a more thorough physical explanation of what actually happens when the object starts rolling?

    Thank you.
  2. jcsd
  3. Aug 10, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    The friction at the edge (surface) applies a moment (force at distance from rotational axis or center of mass) which induces a torque, which induces a change in angular momentum of the mass about the rotational axis.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook