Abstract:  This paper points out the problems existing in the current research of critical angular velocity of rotating spring on a horizontal plane, and gives the physical definition of critical angular velocity of rotating spring. On the basis of deriving the elastic force equation of each point inside the rotating spring, the critical angular velocity and critical length formulas of the rotating spring are deduced from the definition. Then the related problems are discussed.

Key words:  critical angular velocity, critical length, rotation, a spring with mass