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Homework Help: Height in conservation of energy problem

  1. Oct 27, 2016 #1
    1. The problem statement, all variables and given/known data
    A very Slippery ice cube slides in a vertical plane around the inside of a smooth, 20 cm diameter horizontal pipe. The ice cube's speed at the bottom of the circle is 3.0 m/s
    Vi = 3.0 m/s
    Height at top= 2(.20) = .40
    Vf = ?
    2. Relevant equations
    KE(initial) + PE(initial) = KE(final) + PE(final)

    3. The attempt at a solution
    (1/2)mVi^2+0 =(1/2)mVf^2 + mgh
    masses cancel out:
    (1/2)Vi^2-gh = (1/2)Vf^2
    Vi^2-2gh = Vf^2
    sqrt(Vi^2-2gh) = Vf
    Plugging in all my variables I get an answer of: 1.07 m/s
    Answer should be: 2.3 m/s
  2. jcsd
  3. Oct 27, 2016 #2


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    Science Advisor

    I can see one problem.
  4. Oct 27, 2016 #3
    Thank you very much!
    Adjusting for this, I get the correct answer.
  5. Oct 27, 2016 #4
    Check your "Height at top calculation".
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