Balance a Stick on its End on a Finger/Mistake

From ProofWiki
Jump to navigation Jump to search

Source Work

1992: David Wells: Curious and Interesting Puzzles:

The Puzzles:
Henry van Etten
$113$


Mistake

How can a stick be made to balance securely on the tip of a finger?

The solution is given as:

Force the tips of three knives into the stick, so that the knives hang well below the finger.
The centre of gravity of the entire arrangement will then be below the fingertip and will be stable.


Correction

You do not actually need as many as $3$ knives.

$2$ will do just as well.

In fact, any number of knives, as long as the points at which they are forced into the stick form a regular polygon, can be used.


Sources