Nuclear forces between proton proton proton neutron
Well as a first cut protons have positive charge and like charges repel. This overwhelms any gravitational force between them.
Neutrons have no charge so no electrical force between them or between them and protons. The gravitational force is tiny.
As a second cut you might ask why if they repel each other they stick together in the nucleus of an atom. I do not know if your course gets into strong force and weak force but here is a quick description.
https://www.livescience.com/48575-strong-force.html
Nuclear forces, also known as strong forces or strong nuclear forces, are the forces that bind structures together within the atomic nucleus. They are responsible for holding protons and neutrons together, overcoming the electrostatic repulsion between positively charged protons.
In the case of three particles, such as three protons and one neutron, the nuclear forces will act between them. The nuclear force between two protons or between a proton and neutron is attractive, meaning it pulls the particles closer to each other. This force is mediated by particles called mesons, specifically pions.
To explain how to calculate the nuclear forces between three particles, we need to consider the interactions between each pair of particles and then combine them. However, it is important to note that the exact calculation of nuclear forces is complex and requires advanced theoretical models and techniques.
One widely used approach is to use the Yukawa potential, which describes the potential energy of the nuclear force as a function of the distance between the particles. The Yukawa potential includes a term that decreases exponentially with distance, mimicking the finite range of the nuclear force.
To calculate the total nuclear force in a three-proton and one-neutron system, you would need to consider the interactions between each pair of particles, accounting for their charges, masses, and distances. This involves solving intricate equations and requires advanced knowledge of nuclear physics.
In practice, scientists typically rely on more sophisticated theories and computational methods, such as quantum chromodynamics (QCD) or effective field theories, to accurately describe and calculate the nuclear forces in multi-particle systems.
So, while the concept of nuclear forces between three protons and one neutron can be explained, the precise calculation of these forces involves highly complex physics and mathematical techniques that go beyond the scope of a simple explanation.