Motion under different kinds of force

• Bertrand's theorem: In central force motion, the orbits are closed only for inverse square law and Hooke's law.
• The blue cross is the center at which the central force is pointing. As the mass of the interacting object situated at the blue cross is assumed to be much greater than that of the yellow sphere, the blue cross is legitimately regarded as a stationary point.
• If the masses of the two interacting bodies are comparable, they together exhibit a two-body motion

• The author (Chiu-king Ng) has the copyright on all the simulations in this website.
• Email phyAA@phy.hk, where AA is the prime number following 7.
• Last Update:2019-3-20