Inertial properties of the natural forms of an axisymmetric elastic body

It is shown that, during the rotation of an elastic body (e.g., a pendulum) about the axis of symmetry, the natural forms rotate in the body over an angle proportional to the angle of body rotation. The proportionality coefficient depends on the form of the body and the number of the natural form in the case of which body vibrations occur. The effect of dissipative forces is taken into account. A hemispherical shell is considered as an example.