* Newton's First Law of Motion: This law states that an object at rest will stay at rest, and an object in motion will stay in motion at a constant speed and direction, *unless acted upon by a net force*.
* Forces are vectors: This means they have both magnitude (strength) and direction.
* Balanced forces: When forces are balanced, they have the same magnitude but act in opposite directions. This results in a net force of zero.
Examples:
* A book on a table: Gravity is pulling the book down, but the table is pushing back up with an equal and opposite force. The forces are balanced, so the book remains at rest.
* A person standing still: Gravity pulls the person down, but the ground exerts an equal and opposite normal force upward. Again, the forces are balanced, leading to no movement.
Important note: Even when there is no movement, forces can still be present. The key is that they are balanced, resulting in a net force of zero and no change in motion.
