A is farther away from an observer than is B. What will happen if the observer moves his head from right to left?
A) A will seem to move more quickly than B in a direction opposite to that of the observer.
B) B will seem to move more quickly than A in a direction opposite to that of the observer.
C) A will seem to move more quickly than B in the same direction as that of the observer.
D) B will seem to move more quickly than A in the same direction as that of the observer.

Question

Quizplus · Accepted Answer

This is an example of parallax motion. As the observer moves their head from right to left, the angle at which they view A and B changes. Since A is farther away, this change in angle has a greater effect on A's apparent motion than on B's. Therefore, B will seem to move more quickly than A in the direction opposite to that of the observer.

A Is Farther Away from an Observer Than Is B