The orbit in the tennis ball is displayed by the simulation (calculation). A simulation near an actual orbit can be done by having considered the first velocity necessary for the forecast of the orbit, gravitational acceleration, the wind drag, and the spin rotation. It is likely to become help of the understanding of characteristics of balls of a lob, topspin, under a spin, and service, etc. based on kinetics. It is likely to be able to use it for the explanation by the lesson to transmit ..correct answer.. orbit the image for the leader moreover.