Displacement is the straight-line vector from start to end point

Steps:

• Points X and Y are the endpoints of the semicircular track's diameter.
• Displacement magnitude equals the diameter: 2 × radius = 2 × 1.0 m = 2.0 m.
• The path is semicircular, so Y lies directly south of X along the diameter.
• Thus, displacement is 2.0 m due south.

Why B is correct:

• Displacement is defined as the straight-line vector between initial and final positions; for a semicircle, this is the diameter (2r) in the southward direction.

Why the others are wrong:

• A: Omits direction; displacement requires both magnitude and direction as a vector.
• C: 3.0 m exceeds the diameter; confuses with a larger incorrect distance.
• D: 3.1 m approximates the curved path length (πr ≈ 3.14 m), but displacement ignores the path.

Final answer: B