Five sprinters are running in separate straight lanes aligned east–west
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Five sprinters are running in separate straight lanes aligned east–west. At a particular instant, motion sensors measure each sprinter’s instantaneous velocity along the lane:
• Runner A: +9.2ms−1
• Runner B: −8.7ms−1
• Runner C: +8.9ms−1
• Runner D: −9.4ms−1
• Runner E: +9.0ms−1
Assume east is the positive direction. Answer the following, justifying each ranking or calculation.
(a) Rank the five runners from fastest to slowest by speed. If any runners have the same speed, indicate ties clearly.
(b) Identify which runners are moving west and explain how you can tell solely from the given data.
(c) Each runner continues at the listed constant velocity. Calculate how long it takes each runner to travel 100m straight ahead in the direction they are already moving. Present your results in a ranked list from shortest to longest time.
(d) Compare the order you obtained in part (c) to the speed ranking from part (a). Explain any similarities or differences in the two orderings.