The strong nuclear force is responsible for holding the nucleus of an atom together, while the weak nuclear force is responsible for radioactive decay.
The strong nuclear force is much stronger than the weak nuclear force and is responsible for keeping the protons and neutrons in the nucleus together. The weak nuclear force, on the other hand, is responsible for changing one type of particle into another through radioactive decay.
An example of a phenomenon that is influenced by both strong and weak nuclear forces is nuclear fusion, the process that powers the sun and other stars. The strong nuclear force allows for the fusion of two or more nuclei to form a larger nucleus, while the weak nuclear force is responsible for the decay of unstable nuclei.
No, strong and weak nuclear forces can also be repulsive. The strong nuclear force can be repulsive at very short distances between particles, while the weak nuclear force can be repulsive in certain types of radioactive decay.
The existence of strong and weak nuclear forces was inferred through experiments and observations of nuclear reactions. The theories of these forces were developed by physicists such as Enrico Fermi and Hideki Yukawa in the early 20th century.