Final answer:
Dynamic equilibrium is when opposing dynamic forces within a system are equal and opposite, canceling each other out as exemplified by Newton's third law of motion. Correctly defining the 'system of interest' is vital to determine if such internal forces neutralize themselves, affecting the net external force on the system.
Step-by-step explanation:
The concept in which opposing dynamic forces cancel each other out is referred to as dynamic equilibrium. In physics, particularly when exploring Newton's third law of motion, we learn that forces always come in pairs that are equal and opposite, maintaining the momentum of the system unchanged. If a force is exerted on an object, there is a reciprocal force of equal magnitude but in the opposite direction exerted back. For instance, if a teacher pushes a cart, the cart pushes back with an equivalent force. These are internal forces and when considering the system they belong to, they cancel each other out, sustaining a state of no net change in the system.
Understanding dynamic equilibrium is crucial in fields such as engineering, where it is important for structures to be in balance, and in medicine, where body systems must maintain equilibrium to function properly. An example would be a scenario in which the selection of the 'system of interest' affects whether forces cancel. For example, the force the professor exerts on the cart and the force the cart exerts back on the professor are internal to the system and, thus, cancel each other out when the system is defined accordingly. System 1, in this particular context, highlights the importance of defining system boundaries when analyzing forces. Only by correctly defining the system can we see how internal forces negate each other, leaving the net external force unaffected. This principle extends to more complex situations where understanding the interactions and the resultant effect is essential for problem-solving, whether in static or dynamic scenarios.