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A ball weighing 1.0 kg is tied to a stri...


A ball weighing 1.0 kg is tied to a string 15 cm long initially the ball is held in position such that the string is horizontal. The ball is now released. A nail N is situated vertically below the support at a distance L. The minimum value of L such that the string will be would round the nail is.

A

15 cm

B

4 cm

C

9 cm

D

None of these

Text Solution

Verified by Experts

Velocity of bob at C should be `sqrt(5gR)`
`sqrt(5g(R-L))=sqrt(2gR)`
`5(R-L)=2R`
`3R=5L`
`L=(3)/(5)R=(3)/(5)xx15=9cm`
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