Anucleus of helium with mass 5 u breaks up from rest into a nucleus of ordinary helium (mass = 4 u) plus a neutron (mass = 1 u). the rest energy liberated in the break-up is 0.89 mev, which is shared (not equally) by the products. (a) using energy and momentum conservation, find the kinetic energy of the neutron. (b) the lifetime of the original nucleus is 1.0 × 10−21 s. what range of values of the neutron kinetic energy might we measure in the laboratory as a result of the uncertainty relationship?