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प्रश्न
The wheels of a car are of diameter 80 cm each. How many complete revolutions does each wheel make in 10 minutes when the car is traveling at a speed of 66 km per hour? [Use Π = 22/7]
उत्तर
Diameter of the wheel of the car = 80 cm
Radius (r) of the wheel of the car = 40 cm
Circumference of wheel = 2πr
= 2π (40) = 80π cm
Speed of car = 66 km/hour
= (66x100000)/60 cm/min
= 110000 cm/min
Distance travelled by the car in 10 minutes
= 110000 × 10 = 1100000 cm
Let the number of revolutions of the wheel of the car be n.
n × Distance travelled in 1 revolution (i.e., circumference)
= Distance travelled in 10 minutes
n x 80Π = 1100000
`n = (1100000xx7)/(80xx22)`
= (35000)/8 = 4375
Therefore, each wheel of the car will make 4375 revolutions.
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