    Sentence 1: Who invented the formula for  Kinetic Bnergy (KE = 1/2 mv"2) and when  should it be used instead of the formula for  momentum (p = mv) and why?    Sentence 2: Can an electron have zero  distance to the nucleus? If yes then  E=mv‘2/2 - Ke"a/r will be there infinite  energy? Maybe when an atom is fully  shrinked?