Rolling coin
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Susam Pal
Jul 18, 2011, 3:50:42 AM7/18/11
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Rolling coin: http://cotpi.com/p/13/
Some perfectly circular coins are placed in a nearly circular chain.
Each coin touches two other coins in the chain. There is room for at
least one more coin inside the chain.
A new coin is placed inside the chain and rolled around the chain once
completely. The rolling coin touches at least one coin in the chain
throughout the roll. It rolls without slipping. Then this coin is
placed outside the chain and rolled around it in a similar manner.
How many times should we perform these two rolls so that the number of
rotations made by the coin while rolling is twice the number of coins
in the chain?
Some perfectly circular coins are placed in a nearly circular chain.
Each coin touches two other coins in the chain. There is room for at
least one more coin inside the chain.
A new coin is placed inside the chain and rolled around the chain once
completely. The rolling coin touches at least one coin in the chain
throughout the roll. It rolls without slipping. Then this coin is
placed outside the chain and rolled around it in a similar manner.
How many times should we perform these two rolls so that the number of
rotations made by the coin while rolling is twice the number of coins
in the chain?
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