Citation:
Newton's First Law, also known as the law of inertia, states that an object at rest will stay at rest and an object in motion will stay in motion with a constant velocity unless acted upon by an external force.
The tendency of an object to resist changes in its motion.
Force: A push or pull that can cause an object to accelerate or change its state of motion.
Equilibrium: When all forces acting on an object are balanced, resulting in no net force and thus no acceleration.