Abstract: The static equilibrium configuration of the spring-particle system under the action of the gravitational force depends on the effective mass of the system;the eigenvihration frequncies ωn of the system depends on the mass ratio between the spring and the paticle. The mean values of ωn depends on the initial conditions of the system,the different initial conditions lead to different mean values of the ωn.For example, if u（y,0）=u0f（y）=u0y,thenω^2=k/（m2＋1/3m1）. An accurate approximate-calculation formula for θ1=ω1/ω0 is derived.

Key words: Lagrange variable, mass, shape function, eigenfrequncies, initial conditions, mean values