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
Gravitational energy get the total work done by an external force to bring point mass formula_3 from infinity to the final distance formula_10 (for example the radius of Earth) of the two mass points, the force is integrated with respect to displacement: Because formula_13, the total work done on the object can be written as: In general relativity gravitational energy is extremely complex, and there is no single agreed upon definition of the concept. It is sometimes modeled via the Landau–Lifshitz pseudotensor that allows retention for the energy-momentum conservation laws of classical mechanics. Addition of the matter stress–energy–momentum tensor to the Landau–Lifshitz