Final answer:
When a ball on one end of Newton's cradle collides with the next, the action-reaction forces result in the last ball swinging out to a similar height, demonstrating the conservation of momentum and energy.
Step-by-step explanation:
According to Newton's third law of motion, which states that for every action, there is an equal and opposite reaction, the expected result when the ball on one end of a Newton's cradle is dropped is as follows: it will collide with the stationary ball next to it, and nearly all of the momentum and energy will be transferred through the series of balls to the ball on the opposite end. This ball will then swing out approximately to the height of the dropped ball. This illustrates the conservation of momentum and energy within a system, where the only forces acting are internal to the system and hence don't change the system's overall momentum. The 'action' is the force applied by the dropping ball, and the 'reaction' is the nearly equal force with which the last ball is pushed away.
This principle has practical uses beyond the Newton's cradle, such as in analyzing the origin of forces in different systems and ensuring that the total momentum remains constant within an isolated system, as dictated by Newton's laws. One can see similar principles at work in various applications like rocket propulsion and collision analysis.