Abstract
By results of dummy's experiments, there was the point that the normal force at the rotational center (dummy's pastern) became zero when the dummy was in falling. So we proposed a model based on the falling of rigid bar, which was improved both hypothesis of the rotational & free falling and a rigid pendulum. Our models showed that the normal force of rigid bar became zero value by the way of the falling process. When the ratio (friction/normal force) went beyond a coefficient of static friction A μ_0 and an angular θ satisfied with a relation θ_l<θ<COS^<-1>(1/3), the friction force acted to opposite direction so as to counteract a centrifugal force of the falling rigid bar. This inversed frictions being caused by the centrifugal force corresponded to a stress, that stress prevented the dummy from being outthrown. Equations of the falling processes were described by the equations of rotation with using an articulatio ellipsoidea whose solutions were similar to the equations of the rigid pendulum.
