抄録
Slowly spinning coins on the table finally make high frequency noise when they fall down on the table.The author tries to give analytical solution or intuitive explanation using a very simple equation for spinning top he derived. The edge of the coin makes equivalent gravitational torque coefficients to attitude extremely large, this increases nutational mode frequency near at flat attitude. It is shown that the angle between spin axis and angular momentum vector becomes perpendicular both at high and at low spin speed. A simple analytical solution for frequency of the vibration is given.
