1. Not finding help here? Sign up for a free 30min 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!

Ball and a step

  1. Dec 5, 2004 #1
    What is the minimum velocity the ball should have in order to go up the step, considering it doesn't slip. Here's a picture.

    I would be grateful if you could give me a hint.

    Attached Files:

  2. jcsd
  3. Dec 6, 2004 #2
    is it that i didn't explain the problem correctly?

    Please help me!
  4. Dec 6, 2004 #3


    User Avatar
    Science Advisor
    Gold Member

    Your picture is very diffuse. Anyway, If I were you, I will take the momentum (torque) equilibrium at the point of contact between the ball and step. At that point

    [tex] \sum F_i r_i >0 [/tex] in order to enhance the turning of the ball around the wedge.

    Also, you should try with energy conservation (kinetic--->potential) if you want a gross estimation.
  5. Dec 6, 2004 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    You need to break this up a bit:
    You have been told that the ball will NOT slip at the corner; evidently this must mean that the velocity of the contact point of the ball is ZERO, throughout the motion (after contact is has been made)

    A) The collision phase:
    The angular momentum of the ball with respect to the corner must be conserved throughout the collision (why is that).
    This gives you the resultant angular velocity just after the collision, in terms of the initially given parameters.
    B) Post-collision phase:
    Only gravity does work on the system here, due to the no-slip condition.
    Hence, mechanical energy is conserved.

    Good luck&good constitution day to all Spaniards!..:smile:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Ball and a step
  1. Step Potential (Replies: 1)

  2. Algebraic Step (Replies: 10)

  3. Step function (Replies: 3)

  4. Step Force (Replies: 0)