An athlete completes one round of a circular track of diameter 200 metre in 30 second find the the distance travelled by athlete and the magnitude of displacement of the athlete at the end of 30 second
Answers
Explanation:
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.