1. The object is at rest: If an object is stationary, it means the forces acting on it are perfectly cancelling each other out. There's no net force causing it to move.
2. The object is moving at a constant velocity: This might seem counterintuitive, but if an object is moving at a constant speed in a straight line, it also means the forces are balanced. There's no net force causing it to speed up, slow down, or change direction.
Important Note: The two conditions above describe the *net force* acting on an object. Even though the net force is zero, there could still be multiple individual forces acting on the object, as long as they perfectly cancel each other out.
