Final answer:
The given statement involves two observers and two velocities of an object, u and u', representing the object's motion relative to each observer. It relates to the concept of relative motion in physics.
Step-by-step explanation:
The given statement involves two observers and two velocities of an object, u and u'. These velocities represent the object's motion relative to each observer. In physics, the concept of relative motion is used to study how motion is perceived from different frames of reference. The velocities u and u' are measured relative to the observer, and the statement implies that the object's velocity is the same from both observers' perspectives.