* Net Force: The key concept is net force. Net force is the overall force acting on an object, taking into account both the magnitude and direction of all individual forces.
* Equilibrium: An object at rest is in a state of equilibrium, meaning the net force acting on it is zero. This doesn't mean there are no forces, just that they balance each other out.
Examples:
* A book on a table: Gravity pulls the book down, but the table pushes upwards with an equal and opposite force. The net force is zero, so the book stays at rest.
* A hanging picture: The tension in the string holding the picture upwards exactly balances the force of gravity pulling it downwards.
* A magnet holding a paperclip: The magnetic force attracting the paperclip is balanced by the force of gravity pulling it down.
Important Note: Even though the object is at rest, forces are still being applied. If any of the forces change, the object will start to move (accelerate).
