It is difficult to understand the Coriolis force, one of the inertial forces. The main reason is that we cannot experience the Coriolis force in our daily lives. To understand the Coriolis force, we first obtained the trajectory of a free particle in a rotating coordinate system by coordinate transformation of its trajectory in an inertial system. Then, by solving the equations of motion including inertial forces in the rotating coordinate system numerically to obtain the trajectory of the free particle and comparing it with the trajectory obtained by the coordinate transformation, it became possible to understand that the centrifugal force and Coriolis force determine the trajectory in the rotating coordinate system. Furthermore, by visua...