A bottle of Cotnari
The figure above represents a curve drawn on a cilindric surface and is called helix. The distance between two consecutive points of a helix placed on the same axis is constant
and is called pitch.
The pitch of a corkscrew's helix is and the length of a cork is . A man who tries to open a bottle of COTNARI can spin his hand for only 120 degrees. How many moves are required so that the the corkscrew passes through the cork?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
At every rotation of the corkscrew it advances 8mm. The length is 40mm. That means 40/8=5 moves. But the hand spins olny 120 degrees, not 360 degrees which is what a full rotation has. So it will take 3 times more rotations which makes 5*3=15.