A cyclist rides 3 km west then turns and rides 2 km east. The magnitude of the displacement is:
A5 km
B1 km
C2 km
D3 km
Answer & Solution
Correct answer: B. 1 km
1. Displacement depends only on the start and end positions.
2. Taking west as one direction, the two legs partly cancel.
3. Three kilometres out and two kilometres back leaves the rider 1 km from the start.
4. The distance travelled is 5 km, which is the trap answer here.
5. This is exactly the contrast between distance and displacement.
_Source: OpenStax College Physics for AP(R) Courses 2e (CC BY 4.0), Ch 2 'Kinematics', sections 2.1-2.8_
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