Question

    A car is traveling at a speed of 144 km/hr. The car's tires have a diameter of 70 m. How long will it take for the car to complete 12 revolutions of its tires?

    A 65 sec Correct Answer Incorrect Answer
    B 60 sec Correct Answer Incorrect Answer
    C 66 sec Correct Answer Incorrect Answer
    D 56 sec Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, Speed of the tyre = 144 × (5/18) = 40 m/s Circumference of the tyre = 2πr = 2 × (22/7) × (70/2) = 220 metres Time taken by the tyre to make 12 revolution = 12 × (220/40) = 66 seconds

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