Using energy to solve circular motion problems

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  • #1
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Homework Statement



[PLAIN]http://img251.imageshack.us/img251/1764/66016056.jpg [Broken]

Solutions

[PLAIN]http://img213.imageshack.us/img213/6821/99132292.jpg [Broken]


The Attempt at a Solution



Now here is my question, why exactly can we not approach this problem using Energy to part a) by setting spring energy = kinetic energy?

I tried it and I got an answer similiar, except there is a square root
 
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Answers and Replies

  • #2
kuruman
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Now here is my question, why exactly can we not approach this problem using Energy to part a) by setting spring energy = kinetic energy?

I tried it and I got an answer similiar, except there is a square root
Based on what principle should the kinetic energy be equal to the spring energy? Why should there be a 50-50 split of the energy initially added to the mass?
 
  • #3
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Kinetic energy of the stone (the tangential speed) is equal to the spring energy? What do you mean 50-50 split?
 
  • #4
kuruman
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Kinetic energy of the stone (the tangential speed) is equal to the spring energy? What do you mean 50-50 split?
It was your idea.
Now here is my question, why exactly can we not approach this problem using Energy to part a) by setting spring energy = kinetic energy?
Total energy = Kinetic energy + spring energy
If, as you say, spring energy = kinetic energy, then there is a 50-50 split of the total energy. I am wondering why you think that is true.
 

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