# Using energy to solve circular motion problems

## 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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kuruman
Homework Helper
Gold Member
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?

Kinetic energy of the stone (the tangential speed) is equal to the spring energy? What do you mean 50-50 split?

kuruman