Newton's first law of motion, also known as the law of inertia, states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Key Concepts:
Inertia: Inertia is the tendency of an object to resist a change in its state of motion. An object with more mass has more inertia.
Unbalanced Force: When the forces acting on an object are not equal, there is an unbalanced force, which causes a change in the object's motion.