Study of the planetary motion around a fixed gravitational centre. Dependence of the elliptic trajectory on some initial position and initial speed of the planet. Simulation of the planetary motion with velocity and acceleration vectors. Kepler"s second law about swept areas. Who is the fastest planet? Use this piece of software to teach the subject. The help provided is thorough with all calculations, proofs and formulas in a PDF file. The application is bilingual: English and Greek. Created by SHSoft in Visual Basic 6.0 for ShiChuang. You need to run the self-extracting setup program setup_VelocitySelector.exe for the installation of the application. No password is required.