InterviewSolution
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InterviewSolution
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A body of mass m hangs at one end of a string of length l, the other end of which is fixed. It is given a horizontal velocity so that the string would just reach where it makes an angle of 60° with the vertical. The tension in the string at mean position is(A) 2 mg (B) mg (C) 3 mg(D) √3 mg |
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Answer» Answer is (A) 2 mg When body is released from the position (inclined at angle θ from vertical), then velocity at mean position, v = \(\sqrt{2gl(1-cosθ)}\) ∴ Tension at the lowest point = mg + \(\frac{mv^2}{l}\) = mg + \(\frac{m}{l}\) [2gl(1-cos60°)] = mg + mg = 2mg |
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