When a bicycle is moving at a speed of 3 km/hr the circular tire completes 500 full rotations in 17 min. 36 sec. When the circular tire gets detached from the moving bicycle and continues to run freely for 2 minutes 56 seconds at a speed of 0.9 km/hr before coming to a halt, then how many full rotations will it complete before coming to halt?
When a bicycle is moving at a speed of 3 km/hr the circular tire completes 500 full rotations in 17 min. 36 sec. When the circular tire gets detached from the moving bicycle and continues to run freely for 2 minutes 56 seconds at a speed of 0.9 km/hr before coming to a halt, then how many full rotations will it complete before coming to halt? Correct Answer 25
Given:
Bicycle is moving at a speed of 3 km/hr
Circular tire completes 500 full rotations in 17 min 36 sec
Speed of bicycle when moving freely = 0.9 km/hr
Time take to come to halt when moving freely = 2 minutes 56 seconds
Formula used:
Speed = Distance/Time
Calculation:
When the bicycle is moving,
Speed of bicycle = 3 km/hr = 3 × 5/18 = (5/6) m/sec.
Time taken to cover 500 rotations = 17 min 36 sec = 17 × 60 + 36 = 1056 sec
⇒ Total distance covered in 500 rotations = Speed × Time = (5/6) × 1056 = 880 m
⇒ Distance covered in 1 rotation = 880/500 = 1.76 m
Now,
When the tire is detached from the bicycle,
Speed of tire = 0.9 km/hr. = 0.9 × 5/18 = 1/4 m/sec.
Time taken by tire to come to halt = 2 min 56 sec = 2 × 60 + 56 = 176 sec
⇒ Total distance covered by tire before halting = (1/4) × 176 = 44 m
∴ No. of full rotations made by tire before halting = Total distance covered/Distance covered in 1 rotation = 44/1.76 = 25