Final answer:
Without the exact statements from Students A, B, C, and D, it's not possible to identify who is correct, but by understanding the principles of momentum and impulse, we can clarify that the momentum of an object can be changed through the application of an impulse (force over time). For isolated systems, momentum is conserved before and after collisions, and a longer duration of force leads to a greater change in momentum for objects of equal mass.
Step-by-step explanation:
To determine which student correctly understands the concept of momentum and impulse, we should refer to the principles laid out in the question's information. From the details provided, momentum can be changed through the application of force over time. This means impulse, which is the force exerted multiplied by the time over which it's applied (J = FΔt), is directly connected to the change in momentum.
It appears that all students are missing crucial details in their understanding, making it difficult to directly answer which student is correct. However, based on the information, we could infer that the correct understanding involves acknowledging that the total momentum of a system is conserved unless acted upon by external forces, that impulse can change the momentum of an object, and that when no external forces are present, the change in momentum equates to the impulse applied.
In the case of the two air cars, if they are an isolated system, the total momentum before and after the collision would be equal, thus supporting the principle of conservation of momentum. If a force is applied on two objects of equal mass for different durations, the object exposed to the force for the longer time would have a greater change in momentum since impulse is force multiplied by the time.