On the Motion of a Rigid Body with a Fixed Point in a Flow of Particles

The problem of motion of a rigid body with a fixed point in a free molecular flow of particles is considered. It is shown that the equations of motion of this body generalize the classical Euler–Poisson equations of motion of a heavy rigid body with a fixed point, and they are represented in the form of the classical Euler–Poisson equations in the case when the surface of the body in a flow of particles is a sphere. The existence of first integrals in the considered system is discussed.