physicsfun on Instagram: "Vortex II Coin Bank: interplay between potential energy of gravity and conservation of angular momentum- a simulation of a decaying orbit. A favorite inexpensive physics toy and fun with every coin saved! ➡️ Follow the link in my profile for more info on where to get this and other amazing items featured here on @physicsfun #physics #physicstoy #physicsfun #gravitywell #angularmomentum"