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
Energy–momentum relation is consistent with this equation – it is consistent with relativistic mechanics, and is Lorentz invariant. In relativistic quantum field theory, it is applicable to all particles and fields. The Energy–momentum relation was first established by Paul Dirac in 1928 under the form formula_3, where V is the amount of potential energy. The equation can be derived in a number of ways, two of the simplest include: For a massive object moving at three-velocity with magnitude in the lab frame: is the total energy of the moving object in the lab frame, is the three dimensional relativistic momentum of the