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Question
A bucket is raised from a well by means of a rope which is wound round a wheel of diameter 77 cm. Given that the ascends in 1 minute 28 seconds with a uniform speed of 1.1 m/sec, calculate the number of complete revolutions the wheel makes in raising the bucket. (Take π =22/7)
Solution
Distance moved by the bucket = speed x Time
= [ 1.1 x 88 ] metre ...[ ∵ 1 min 28 sec = 60 + 28 = 88 sec.]
= 96.8 metres
Circumference of wheel = 2πr
= `2 xx 22/7 xx 77/2 "cm" ...( ∵ r = d/2 = 77/2 "cm")`
= 242 cm
= 2.42 metres
∴ Number of complete revolutions the wheel makes in rising the bucket
= `"Distance"/"Circumference"`
= `(96.8/2.42)` = 40.
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