Which of the following correctly describes Newton's First Law of Motion?

Newton's First Law of Motion states that an object will remain at rest or continue to move at a constant velocity in a straight line unless acted upon by a net external force. This law emphasizes the concept of inertia, which is the tendency of an object to resist changes in its state of motion.

In practical terms, if no net force is applied to an object (meaning all forces acting on it are balanced), it will not change its motion. For example, a book resting on a table will remain in place until someone applies a force to it, such as picking it up or pushing it. Similarly, a rolling ball will keep rolling in the same direction and at the same speed unless friction, a wall, or another force stops it or changes its direction.

This principle is foundational in understanding motion and the behavior of objects in different states. The other options refer to different laws or concepts: force and acceleration relate to Newton's Second Law, while the statement about actions and reactions pertains to Newton's Third Law.