A steel ball rolls down an incline into a loop-the-loop of radius R. What is the minimum speed the ball must have at the top of the loop in order to stay on the track? (the ball has a radius r and starts at a height of h)(adsbygoogle = window.adsbygoogle || []).push({});

This is a similar image to the one in my book:

http://img98.imageshack.us/img98/1876/1m40209ji.th.jpg [Broken]

I'm not sure how to solve this question. But I think it has something to do with conservation of energy. I tried doing that and got:

v = square root of (v_{0}^{2}- 20/7 gR)

but the answer is the square root of (gR), which is must simpler than my answer...so I must be doing something wrong.

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# Loop the loop

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