Core Idea PS2
Motion and Stability: Forces and Interactions
How can one explain and predict interactions between objects and within systems of objects?
Interactions between any two objects can cause changes in one or both of them. An understanding of the forces between objects is important for describing how their motions change, as well as for predicting stability or instability in systems at any scale. All forces between objects arise from a few types of interactions: gravity, electromagnetism, and the strong and weak nuclear interactions.
https://www.nap.edu/read/13165/chapter/9#113