A physics research group compiled the following four nuclear reactions observed in different settings.
Reaction I: 14N+α→17O+p
Reaction II: 235U+n→92Kr+141Ba+3n
Reaction III: 226Ra→222Rn+α
Reaction IV: 2H+3H→4He+n
Assume that for each reaction all conservation laws are satisfied and that the products are initially at rest relative to the reactants unless kinetic energy is explicitly released.
(1) Classify each reaction as fusion, fission, or radioactive decay, and indicate whether it is spontaneous or induced.
(2) For each reaction, state qualitatively whether the net nuclear potential energy of the system increases or decreases, and infer whether the reaction is exothermic or endothermic.
(3) Select one reaction that is dominated by the strong nuclear force throughout the entire interaction distance and one in which electrostatic repulsion plays a significant opposing role. For each selection, explain how the balance between these forces influences both the likelihood of the reaction and the energy outcome.