Final answer:
Newton's second law applies with non-zero values when the object is accelerating, indicating that a net force is acting on it. The law is described by the equation Fnet = ma, showing the relationship between force, mass, and acceleration.
Step-by-step explanation:
For Newton's second law of motion to apply with non-zero values, it is essential that the object in question is accelerating. If the acceleration is zero, the net external force is also zero. However, when an object's acceleration is not zero, it indicates that a net force is acting on it, and Newton's second law can be expressed using the formula Fnet = ma, where Fnet is the net force, m is the mass of the object, and a is the acceleration. This law fundamentally implies that the change in motion, i.e., acceleration, is proportional to the net force applied and occurs in the direction of this force.