Newton's cradle Newton's cradle Newton’s cradle is a device that demonstrates conservation of momentum and energy using a series of swinging spheres. When one sphere at the end is lifted and released, it strikes the stationary spheres, transmitting a force through the stationary spheres that pushes the last sphere upward. The last sphere swings back and strikes the still nearly stationary spheres, repeating the effect in the opposite direction. The device is named after 17th-century English scientist Sir Isaac Newton. It is also known as Newton's balls or Executive Ball Clicker. A typical Newton's cradle consists of a series of identically sized
Relativistic angular momentum of the object's center of mass. Since "T" is the energy density of the object, the spatial coordinates of the center of mass are given by Setting "Y" = X obtains the orbital angular momentum density about the centre-of-mass of the object. The conservation of energy–momentum is given in differential form by the continuity equation where ∂ is the four gradient. (In non-Cartesian coordinates and general relativity this would be replaced by the covariant derivative). The total angular momentum conservation is given by another continuity equation The integral equations use Gauss' theorem in spacetime The torque acting on a point-like