Abstract: The dynamic effect of the fluid in the constant rotation of the fluid is different from that of the stationary state. It is mainly embodied in the change of the pressure inside the liquid and the additional buoyancy，which can be called " centrifugal buoyancy" . We discuss V-shaped tube inertial centrifugal force demonstration instrument in the depth of the ball movement in-depth discussion，by solving the surface integral obtained by " centrifugal buoyancy" formula. Then we find the equation of motion and the phenomenon of quantitative analysis of the interpretation of the experiment.

Key words: non-inertial system, inertial centrifugal force, centrifugal buoyancy, damping motion