Final answer:
The question involves the directional rule of road traffic, which aligns with principles of physics where movement and force directions are often represented by vectors, graphically depicted as arrows.
Step-by-step explanation:
A white arrow painted on a lane indeed signifies that you must only move in the direction of the arrow. This is a rule of the road and a practical application of understanding direction in motion, which is a concept in physics. If we think about this in physical terms, the arrow could be likened to a vector, which in physics is represented by an arrow that has both direction and magnitude. Vectors are important in describing one-dimensional motion, such as that of cars on a straight road or trains on tracks. In science, we also use arrows to indicate direction in several other contexts, such as pointing out the direction in which ions move along a concentration gradient. Overall, the usage of arrows to denote direction is a visual representation that transcends multiple disciplines, from traffic rules to scientific descriptions of motion and forces.