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प्रश्न
A roller has a diameter of 1.4 m. Find :
(i) its circumference ;
(ii) the number of revolutions it makes while travelling 61.6 m.
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उत्तर
Diameter = 1.4 m
r = `1.4/2 = 0.7` m
∴ Circumference of roller = `2pir`
= `2 xx 22/7 xx 0.7 = 4.4` m
Revolutions made in 4.4 m distance = 1
Revolutions made in 1 m distance = `1/4.4`
Revolutions made in 61.6 m distance
= `1/4.4 xx 61.6 = 616/44 = 14`
Hence (i) 4.4 m (ii) 14
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