A sphere moving on a smooth horizontal surface (the xy-plane) impacts a set of 13 cubes at rest on the same surface. This impacts leads to a number of subsequent impacts among these cubes. The ...

In the 1600s, Kepler proposed that the momentum of sunlight was the reason that the visible tails of comets pointed away from the sun. Beyond this optical linear momentum, in the early 1900s, Poynting ...