Final answer:
The weak nuclear force is responsible for nuclear decays, while the strong nuclear force holds the nucleus together in an atom.
Step-by-step explanation:
The weak nuclear force is found within nucleons such as protons and neutrons and is responsible for nuclear decays. It acts over very small distances and is involved in reactions that result in the production of neutrinos.
The strong nuclear force, on the other hand, is significant for an atom because it holds the nucleus together. It acts between protons, between neutrons, and between protons and neutrons. Without the strong nuclear force, the electrostatic repulsion between protons would cause the nucleus to break apart.