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Physics question on energy - need help !

  1. Sep 29, 2013 #1
    1. The problem statement, all variables and given/known data
    Hello All !

    I have this question which I cant seem to get the correct ans to.. maybe Im missing something.. (Please refer to attachment)


    2. Relevant equations

    POtential energy = mass x g x h

    3. The attempt at a solution

    ok initial amt of energy = m x g x h

    final energy state =( mgh/4 + mgh/4 )= mgh/ 2

    so mgh - mgh/2 = mgh/2 (my ans)

    apparently correct ans is mgh/4

    help , pls ? thanks !
     

    Attached Files:

  2. jcsd
  3. Sep 29, 2013 #2

    gneill

    User Avatar

    Staff: Mentor

    Hi nish123, Welcome to Physics Forums.

    When dealing with changes in potential energy, you want to consider the change in elevation of the center of mass.
     
  4. Sep 29, 2013 #3
    ahh, got it!... thanks a ton
    gneill and
    ResscuedByMary

    point i was missing was "When dealing with changes in potential energy, you want to consider the change in elevation of the center of mass."


    Thanks again !!
     
  5. Sep 29, 2013 #4
    thanks ResscuedByMary i now understand your explanation too...

    "When dealing with changes in potential energy, you want to consider the change in elevation of the center of mass." was told by
    gneill as above... thanks both !
     
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