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A boy ties a stone of mass 100 g to the end of a 2 m long string and whirls it around in a horizontal plane. The string can withstand the maximum tension of 80 N. If the maximum speed with which the stone can revolve is π K rev. / min . The value of K is (Assume the string is massless and unstretchable)

1. 400
2. 300
3. 600
4. 800

Correct answer: 600

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