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Diameter of a car wheel is 21 cm. A car driver moving at the speed of 66 km/hr takes 36 seconds to reach a destination. How many revolutions will the wheel make during the journey?
- A1800
- B1500
- C1200
- D1000
Answer not set
Discussion 1
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CCommunity
Given, speed of the car = 66 km/h and diameter of wheel = 21 cm
So, radius of wheel (r) = 21/2 = 10.5 cm
As we know, Distance = speed × time
Distance covered by car in 36 sec = 66 × 5/18 × 36 = 660 meter
As we know, circumference of circle = 2πr
Thus, Circumference of wheel = 2 × 22/7 × 21/2 = 66 cm
∴ No of revolutions = distance/(circumference of wheel) = (660 × 100)/66 = 1000
So, radius of wheel (r) = 21/2 = 10.5 cm
As we know, Distance = speed × time
Distance covered by car in 36 sec = 66 × 5/18 × 36 = 660 meter
As we know, circumference of circle = 2πr
Thus, Circumference of wheel = 2 × 22/7 × 21/2 = 66 cm
∴ No of revolutions = distance/(circumference of wheel) = (660 × 100)/66 = 1000