1. An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s?
Answers
Answer:
Given parameters
The diameter of the circular track = 200 m
Radius (r) = 200/2
r = 100 m
Time is taken by an athlete to complete one round = 40 seconds.
Displacement = ??
Speed = Distance/Time
Total time athlete moves – 2 min 20 seconds
2 min 20 seconds = 2 × 60 + 20
2 min 20 seconds = 140 seconds
Need to find the distance covered in one round
Distance covered in one round = Circumference of circle
Distance covered in one round = 2πr
Distance covered in one round = 2
Distance covered in one round = 2 × 100π
Distance covered in one round =200π
Time is taken by an athlete to complete one round = 40 seconds.
Number of rounds completed in 140s = 140/40
Number of rounds completed in 140s = 35
Distance covered = 3.5 × circumference
Distance covered = 3.5 × 2πr
Distance covered = 3.5 × 2 × 3.14 × 100
Distance covered = 2200 m
Hence, the distance covered at the end of 2 min 20 seconds is 2200 m or 22 km.
And displacement is 200 m as it returns to the initial position.