When a net force is zero, the term is known as equilibrium rule.
This video explains how vectors are used to figure out forces and equilibrium. Force-push or pull. Net force- when more than a single force acts on an object. Vector- Arrows that are drawn to scale.
Newton's First Law of Motion stated that...Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a non-zero net force.
Galileo believed that if there is no interference with a moving object, it will keep moving in a straight line forever; no push, pull, or force of any kind. So, he tested this experiment by experimenting with the motions of various objects on plane surfaces tilted at various angles.
Copernicus reasoned that the simplest way to account for the observed motions of the sun, moon, and planets through the sky was to assume that Earth (And other planets) circles around the sun.
Aristotle divided motion into two main classes: natural motion and violent motion. Natural Motion: Every object in the universe has a proper place, determined by its 'nature'; any object not in its proper place will 'strive' to get there. Violent Motion: Imposed motion. Aristotle taught that all motions are due to the nature of the moving object or due to a sustained push or pull. *An object will stay in place unless subjected to an force.