In: Physics
4) A nucleus of radioactive radium (226Ra), initially at rest, decays into a radon nucleus (222Rn) and an alpha-particle (a 4He nucleus). If the kinetic energy of the alpha-particle is 6.72 × 10^ -13 J, what is (a) the recoil speed of the radon nucleus, and (b) its kinetic energy? The superscripts indicate, roughly, the mass of each nucleus in unified mass units (u), where 1 u = 1.66 × 10^ -27 kg.