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: Rolling motion

  1. Feb 1, 2012 #1
    1. The problem statement, all variables and given/known data
    A uniform sphere rolls down a 30 degree incline θ from height h. Initially, the solid is at rest. Find the acceleration for the center of the mass of the solid.

    I am not sure where to start with this problem. I started with the energy formulas, but I am not sure how to find the acceleration of the center of mass from there. I just need a guide on what formulas or setup to use, thanks!

    2. Relevant equations
    Translational and rotational motion equations


    3. The attempt at a solution
    K_i=mghsin30
    K_f=1/2mv^2+1/2Iω^2

    then I solved for v:
    v=radical(10/7*ghsin30)
     
    Last edited: Feb 1, 2012
  2. jcsd
  3. Feb 1, 2012 #2

    ehild

    User Avatar
    Homework Helper

    Hi, physikx,

    The potential energy is mgh (h is the height of the (slope). Correct your result for v.

    V is the speed of the CM at the end of the slope. Find the length travelled, and use the relation s=v^2/(2a) to determine the acceleration of the CM.

    ehild
     
  4. Feb 1, 2012 #3
    Hey ehid,

    Thank you so much for the help! I was able to setup the problem and get the answer. I really appreciate the guidance.

    Peace
     
  5. Feb 1, 2012 #4

    ehild

    User Avatar
    Homework Helper

    You are welcome.

    ehild
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook